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How to Clean Oxidised PAL SNES Cartridge Contacts Without Damaging the Board

May 21, 2026 • 28 min read
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Dan Cole — Technical Editor, RetroInHand

Last updated: May 2026

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Why Your PAL SNES Cartridge Won’t Load (And Why the Answer Is Almost Always the Contacts)

A few years back I picked up a boxed copy of Terranigma at a car boot in Coventry for ÂŖ8. The seller swore it worked. I got home, slotted it into my PAL SNES, and got nothing — blank screen, solid power light, complete silence. My first instinct was to assume the worst: dead battery, corrupted ROM, damaged connector on the console itself. I spent twenty minutes testing other carts before I bothered to look at the Terranigma board properly. When I finally opened it up, the contacts were almost black. Not a little grey. Jet black, with a faint greenish tinge around the edges. An hour later, after cleaning those contacts properly, it booted first time and saved without complaint. I’ve since bought it for another ÂŖ40 in a charity shop because I left that first copy in a box and couldn’t find it. Lesson learned on multiple fronts.

Oxidised contacts are the single most common reason a PAL SNES cartridge fails to load, and they’re almost always fixable. The Super Nintendo’s edge connector contacts are gold-plated over a nickel substrate, which means they resist corrosion better than bare copper — but they are not immune. Thirty-plus years of storage in lofts, garages, damp sheds, and the occasional flood have left a huge proportion of the PAL SNES library in various states of oxidation. The PAL versions of carts are no worse than NTSC in terms of materials, but they’ve typically had rougher storage lives in British homes, and the UK climate does the contacts no favours.

The good news is that cleaning SNES cartridge contacts is genuinely one of the most approachable jobs in retro hardware maintenance. You don’t need a soldering iron. You don’t need specialist equipment beyond a single security screwdriver. What you do need is the right approach, the right chemicals, and a clear understanding of what you’re actually removing — and what you absolutely must not do. I’ve seen people wreck the gold plating on valuable carts by using the wrong abrasive, and I’ve seen others waste time with methods that clean the surface but leave the oxidation sitting right underneath. This guide covers everything properly, step by step, so you can get your games running without causing any damage in the process.

What Actually Causes SNES Cartridge Contact Oxidation

Before you start cleaning anything, it’s worth understanding what you’re dealing with — because not all contact problems look the same, and the correct approach depends on what you’re actually seeing.

The chemistry of gold contact degradation

The contacts on a PAL SNES cartridge are electroplated with a thin layer of gold, typically somewhere between 0.05 and 0.25 microns thick, over a nickel barrier layer, over the base copper of the PCB traces. Gold itself doesn’t oxidise — that’s essentially the whole point of using it. What you’re seeing when contacts look dark or discoloured isn’t gold oxide. It’s a combination of things: oxidation of the nickel or copper showing through microscopic gaps or wear in the gold layer, surface contamination from oils, dust and general atmospheric grime, and in worse cases, actual corrosion from moisture — which attacks the exposed base metals and can migrate under the gold plating from the edges of the contact strip.

The greenish tinge you sometimes see is copper corrosion — verdigris — working its way up from below. That’s a more serious situation than simple surface grime and needs a slightly different approach. The dark grey-to-black discolouration on most carts is typically a mix of tarnished nickel and compacted dirt. Neither is a death sentence for the cartridge, but they need to be addressed differently.

Why PAL carts specifically tend to be worse

In my experience, PAL SNES carts that have lived their whole lives in the UK or mainland Europe tend to have contacts in worse overall condition than equivalent NTSC carts from the same era, even accounting for storage quality. Part of this is simply climate — the UK’s damp, variable weather creates conditions where moisture infiltrates plastic shells more readily than the drier storage environments common in parts of the US or Japan. Part of it is the culture around game storage: in the 1990s, British parents were far more likely to chuck a cartridge in a drawer or a carrier bag than keep it in its box. And the PAL SNES library has a higher proportion of games that were heavily played by kids, handed around between friends, and generally treated with zero ceremony.

The plastic shell on PAL carts is identical in material to NTSC versions — the same ABS plastic that is prone to the yellowing discussed in our guide on how to fix yellowing on a PAL Mega Drive without damaging the plastic, albeit on a smaller scale. That yellowing is often a sign that the cart has had significant UV and heat exposure — which also accelerates contact degradation, particularly where the shell has minor cracks or gaps near the connector slot.

What You Need: Full Equipment List Before You Start

Don’t skip this section. The single biggest mistake I see people make is grabbing whatever cleaning fluid happens to be under the kitchen sink and a random bit of cloth, then wondering why the contacts look worse or why the cart still won’t load. The right tools matter enormously here. Every item on this list is either doing a specific job or preventing a specific type of damage.

Essential tools

  • 3.8mm Gamebit security screwdriver — Non-negotiable. PAL SNES cartridges use proprietary security screws, not standard Philips or flathead. You cannot open the shell without this. Generic versions cost around ÂŖ3–ÂŖ5 on Amazon and they work fine; you don’t need a premium version for this job. The 4.5mm Gamebit is for the console itself — different size, don’t mix them up.
  • Isopropyl alcohol (IPA) at 99% concentration — This is your primary cleaning solvent. It must be 99% or as close as possible. The 70% stuff sold in pharmacies for skin disinfection has too much water content and can cause flash corrosion on exposed base metals. It will also leave residue. A 500ml bottle of 99% IPA costs around ÂŖ8–ÂŖ12 online and will last you years of cartridge cleaning.
  • Lint-free cotton buds or swabs — Standard cotton buds from the chemist work but shed fibres. Purpose-made lint-free electronics swabs (sometimes sold as foam-tipped swabs) are better because they don’t leave cotton strands on the contacts, which can cause their own connection problems later. A pack costs around ÂŖ4.
  • Soft, clean, lint-free cloth — For wiping down the overall board and shell. An old glasses-cleaning cloth is ideal. Kitchen roll will do in a pinch but again, lint.
  • Bright light source — A decent desk lamp or a headtorch. You need to see exactly what you’re dealing with before and after cleaning. I use a clip-on LED ring light positioned directly above my work surface.
  • Magnifying glass or loupe — Not strictly essential but genuinely useful for checking the contacts before and after. Even a cheap 10x jeweller’s loupe (ÂŖ3–ÂŖ5) is enough to spot the difference between surface contamination and actual plating damage.

For moderate to heavy oxidation

  • DeoxIT D5 contact cleaner — This is the professional standard for contact cleaning in electronics. It’s a contact cleaner and protectant combined — it dissolves oxidation chemistry, cleans the surface, and leaves a very thin protective coating. A 142g spray can costs around ÂŖ15–ÂŖ18 but lasts a very long time if you use it correctly (a tiny amount per application). This is what I reach for first on anything with visible dark oxidation.
  • Fibreglass scratch pen / fibreglass pencil — For contacts with stubborn, built-up oxidation that won’t shift with chemicals alone. This is essentially a bundle of fine fibreglass strands in a pencil body. You rub it gently across the contact to mechanically abrade the top layer of oxidation. It is effective but must be used carefully — too much pressure, too many passes, and you’ll start removing gold plating rather than just oxidation. Cost around ÂŖ4–ÂŖ7.
  • Contact burnishing eraser or Staedtler eraser — A white vinyl eraser (specifically a Staedtler Mars plastic, not a cheap rubber one) or a proper contact burnishing eraser works well for light mechanical cleaning as an alternative to the fibreglass pen. Softer, so lower risk — but less effective on serious oxidation.

Things you must not use

  • WD-40 — I know, I know. But WD-40 is not a contact cleaner. It’s a water displacer and light lubricant with hydrocarbon solvents in it. It will temporarily improve a connection by displacing surface moisture and grime, but the petroleum residue it leaves behind attracts more dust, gums up over time, and can actually make things worse within weeks. Never use it on electronic contacts.
  • White spirit, acetone, or nail varnish remover — These will attack the cartridge shell plastic, potentially dissolve PCB lacquer, and can strip solder mask from the board. Acetone in particular is aggressive and will cloud or crack the plastic shell on contact.
  • Sandpaper — This one should be obvious but I’ve seen it recommended in forum posts. Even very fine sandpaper will destroy the gold plating in a single pass. Do not use it.
  • Metal polish (Brasso, Autosol, etc.) — These contain abrasives designed for polishing thick metal surfaces. Far too aggressive for thin gold plating. They also leave a residue that’s difficult to fully remove.
  • Pencil eraser (pink rubber type) — The pink rubber erasers common in stationery shops are abrasive enough to scratch the gold plating and leave rubber particulate in the contact area. The white vinyl Staedtler mentioned above is a safe alternative. Pink rubber ones: no.
  • Cotton wool balls — They shed fibres continuously and are nearly impossible to work with precisely enough on the narrow contact strips.

Step-by-Step: How to Open a PAL SNES Cartridge Safely

The PAL SNES cartridge shell is a good design — two halves held together by screws, with a PCB that slides out cleanly once opened. Nothing is glued, nothing is heat-staked, and the board itself has a generous connector tab that’s easy to work on. Compared to, say, opening a Game Boy cartridge (which uses even smaller security screws and has a board that can slide around annoyingly), the SNES cart is a pleasure to work with.

Step 1: Gather your tools and set up your workspace

Before you touch the cart, set up a clean, well-lit workspace. Use a flat, non-static surface — a wooden desk is fine; a metal workbench isn’t ideal unless you’re grounded. Lay out a clean cloth to work on. Put your IPA, swabs, and screwdriver within reach. This sounds like fussing but it genuinely matters: I once knocked a bottle of IPA across a PCB I had open because I hadn’t given myself enough clear space, and while IPA dries clean, the sudden flood of liquid across the board was not relaxing.

If you’re working on a particularly valuable cart — a complete-in-box Chrono Trigger, an Earthbound, anything above ÂŖ50 — consider wearing nitrile gloves. The oils from your skin can recontaminate contacts you’ve just cleaned, and fingerprints on a freshly cleaned gold surface will start oxidising again faster than a clean surface will.

Step 2: Identify the screw positions

Turn the cartridge over so the label faces down. On a standard PAL SNES cartridge, you will see one security screw in the centre-bottom of the cart. Some later carts or third-party shells have two screws. The screw is recessed inside a circular well, which is why standard screwdrivers can’t reach it even if you somehow found one the right diameter. Your 3.8mm Gamebit driver should seat snugly into the screw head. If it spins without biting, the screw may be slightly larger — check you haven’t accidentally grabbed a 4.5mm bit.

Step 3: Remove the screw and open the shell

Turn the screw anticlockwise. It will offer some resistance the first time if the cart hasn’t been opened before — that’s normal. Once the screw is out, put it somewhere you will not lose it. I keep a small ceramic dish on my bench specifically for screws. A glass ramekin works equally well. Losing Gamebit screws is miserable and replacements are not always easy to source.

With the screw removed, the two halves of the shell will separate easily. There’s no clip mechanism to undo. Pull them apart gently — the front half (label side) typically comes forward, and the back half stays put with the PCB sitting loosely inside. Don’t force anything. If there’s resistance, check you’ve removed all screws; some carts have screws hidden under labels (rare on original Nintendo PAL carts but common on some bootlegs and repros).

Step 4: Remove the PCB from the shell

The PCB sits in a plastic tray within the back half of the shell. It simply lifts out. Handle it by the edges — not by touching the contact strip, not by touching any of the chips, and not by the label side. The contact strip runs along the bottom edge of the board and is typically 62 contacts wide on a standard PAL SNES cart. Set the board down on your clean cloth, contact strip facing towards you.

Take a moment now to actually look at the contacts under your bright light. Take the magnifying glass if you have it. You’re assessing the severity of what you’re dealing with before you start, because this determines which cleaning method you’ll use.

Assessing Contact Condition: What You’re Actually Looking At

Not all dirty contacts are the same, and throwing your most aggressive cleaning method at everything by default is how you end up damaging boards that only needed a gentle wipe.

Level 1: Light surface contamination

Contacts look slightly dull rather than properly shiny, possibly with fingerprints or smearing visible. No dark spots, no discolouration beyond a slight greyness. The gold plating is visually intact. This is the majority of PAL carts that have been stored reasonably well. These need nothing more than IPA and a clean swab.

Level 2: Moderate oxidation

Contacts are noticeably dark grey, possibly with patches of black. Still relatively uniform. No green colouration. The gold may be visibly thinner in areas where the cart has been frequently inserted and removed. This is what most charity shop and car boot finds look like. IPA alone may not fully shift this — you’ll likely need DeoxIT D5, or IPA plus gentle mechanical cleaning with the white eraser or burnishing stick.

Level 3: Heavy oxidation or corrosion

Contacts are heavily discoloured — dark brown, black, or showing greenish areas. There may be visible pitting. The green colouration indicates copper corrosion working its way up from below the gold layer, which suggests the plating has been compromised in those areas. This level requires the fibreglass pen for mechanical removal, followed by chemical cleaning. Be prepared for the possibility that some contacts may be damaged beyond full recovery — though even heavily corroded carts often work once cleaned, because the SNES doesn’t need every single contact to be perfect, only the signal lines to be making contact.

Level 4: Physical damage

Contacts are bent, cracked, or have visible PCB trace damage. Cleaning won’t fix this. Bent contacts can sometimes be carefully straightened with a wooden toothpick (never metal). Cracked or lifted traces need a solder repair, which is a different job entirely — but if you’re interested in going further with PCB repair, understanding basic soldering fundamentals is the next logical step.

Step-by-Step: The Cleaning Process

Now we get to the actual cleaning. I’ll walk through this from the gentlest approach to the most aggressive, in order. Always start with the gentlest method and escalate only if it hasn’t worked. You cannot un-remove gold plating.

Step 5: First wipe with isopropyl alcohol

Dampen a lint-free swab with 99% IPA. Not soaking wet — you want it damp enough that it’s clearly applying liquid, but not dripping. Too much IPA pooling on the board isn’t dangerous (IPA evaporates clean) but it makes it harder to see what you’re doing and increases the chance of liquid getting into through-holes on the PCB.

Hold the PCB firmly in one hand with the contact strip facing up. With the IPA-dampened swab, wipe along the contact strip using a single, firm stroke from one end to the other, following the direction of the contact strips (i.e., along the long axis of the contact strip, not across it). Do not scrub in circles. Do not go back and forth vigorously. A single firm wipe in one direction is the correct motion — it lifts contamination off the contact surface rather than smearing it into the gaps between contacts.

Look at the swab after the first wipe. If it’s come away heavily discoloured — dark grey or black — that’s contamination you’ve removed. Get a fresh swab and repeat. Keep going until the swab comes away with minimal discolouration. For Level 1 contamination, this is often all you need.

Let the contacts air dry for at least two minutes before assessing. IPA evaporates quickly at room temperature, but don’t rush this — you want the surface fully dry before you make any judgement about what’s left.

Step 6: Assess the result under bright light

Under your desk lamp, look at the contacts again. Are they uniformly shiny? Are there any remaining dark spots or patches of discolouration? Run a clean, dry swab across the contacts and check whether it picks up any more material. If the contacts look good and the dry swab comes away clean, you’re done with the chemical cleaning phase and can move to Step 10 (reassembly).

If there are still visible dark patches, you need to move to the next level. Don’t be disheartened — most carts need more than one pass.

Step 7: Apply DeoxIT D5 for moderate oxidation

DeoxIT D5 is the step that makes the biggest difference on genuinely oxidised contacts, and it’s the one most guides skip because it costs more than IPA. This is a mistake. For carts with visible grey-to-black oxidation that IPA alone hasn’t shifted, DeoxIT is transformative.

Shake the can well. Apply a tiny amount — and I mean tiny, a single short burst from a few centimetres away — to a clean swab. You want the swab just barely damp with it, not saturated. Apply to the contacts in the same single-stroke motion as before. You’ll notice the DeoxIT has a slightly oily quality compared to IPA — that’s the protectant component. It clings to the surface slightly rather than running off.

Wait thirty seconds. Then wipe firmly along the contacts with a fresh, dry swab. You should see significant dark material lifting off onto the swab. Repeat with fresh swabs until clean. Follow up with a final light wipe of IPA to remove any excess DeoxIT residue from the contact surface — a very thin film is fine and acts as a protectant, but you don’t want a visible heavy residue sitting on the contacts.

One important note on DeoxIT: don’t spray it directly onto the board. Always apply to the swab first. Direct spray means you have no control over the quantity or where it goes, and getting DeoxIT into electrolytic capacitors or under chip legs isn’t ideal. Apply to swab, apply swab to contact. That’s the method.

Step 8: Mechanical cleaning for heavy oxidation (fibreglass pen)

If you’re dealing with Level 3 oxidation — stubborn black or green-tinged contacts that haven’t fully cleared with chemical cleaning alone — the fibreglass scratch pen is your next tool. This is where you need to be most careful, because this is where damage can occur if you’re not paying attention.

First, use the pen on the worst-affected contacts only — not across the whole strip as a matter of course. Identify the specific contacts that remain heavily discoloured and work only on those.

Hold the PCB firmly on your work surface. Apply the fibreglass pen to the discoloured contact with light pressure — lighter than you think you need. Use a gentle back-and-forth motion along the length of the contact strip, not across the contacts. Count your strokes. Five strokes maximum per contact area before you reassess. Look at the surface. Is the oxidation shifting? You should see the contact brightening.

Here is where I made a serious mistake on my first attempt at this, years ago: I was cleaning a fairly beaten-up PAL copy of Super Metroid and got impatient with the fibreglass pen, pressing too hard and going over the same contacts about twenty times. I stripped the gold plating off three contacts entirely — I could see the nickel layer underneath, and eventually the copper showing through. The cart still worked because those contacts happened to be on redundant lines, but I got lucky. Five strokes, light pressure, reassess. Repeat if necessary but stay disciplined.

After mechanical cleaning, always follow up with an IPA wipe to remove fibreglass debris — those tiny glass fibres sitting on the board are conductive enough to potentially cause shorts if they bridge contacts, and you want them completely removed. Follow with DeoxIT if available, then a final IPA wipe.

Step 9: White vinyl eraser as a gentler mechanical option

If you don’t have a fibreglass pen, or if you want a softer approach for contacts that are only moderately discoloured, a Staedtler Mars plastic white vinyl eraser works reasonably well. Cut a small piece off the block — about 5mm wide — so you have a clean, fresh edge. Work along the contact strip with gentle strokes, following the contact direction. Don’t press hard. The vinyl compound is softer than fibreglass and removes far less material per stroke, which is both its strength and its limitation — it’s safer but needs more passes.

The main hazard with erasers is eraser crumble. Vinyl erasers shed small particles of rubber compound as you work, and these particles can bridge contacts or get into PCB through-holes. After using an eraser, blow away the debris carefully (or use a clean, dry paintbrush) and then do an IPA wipe to clear any remaining residue. Check under magnification that no eraser particles are sitting between contacts.

Step 10: Final inspection before reassembly

Before you put the cart back together, do a final, thorough inspection. Under bright light, the contact strip should look visibly cleaner than when you started — ideally a warm gold colour across all contacts. There may be slight variation in brightness between contacts depending on how worn the plating is in different areas; that’s normal and doesn’t indicate a problem. What you’re looking for is the absence of the dark or black patches that were causing the connection issues.

Run a clean, completely dry swab once more across the full contact strip. If it comes away with zero residue — clean swab, no discolouration — you’re ready to reassemble. If it still picks up significant material, repeat the appropriate cleaning step.

Also check the rest of the board while you have it out. Look for any signs of battery acid leakage from the SRAM backup battery (usually a CR2032 or CR2025 soldered to the board) — this appears as a white crystalline residue around the battery holder. If you see this, cleaning the contacts won’t save the cart if the battery has already damaged nearby traces. Check the electrolytic capacitors for bulging or crusty residue at their bases. Neither of these is something you fix in this cleaning session, but it’s worth knowing the full state of what you have.

Step-by-Step: Reassembly

Step 11: Refit the PCB into the shell

Once your contacts are clean and completely dry, lower the PCB back into the rear half of the shell. It will only seat one way — the contact strip faces towards the open end of the shell (the bottom of the cart), and the board sits flush in the plastic tray. Don’t force it. If it’s not seating easily, check the orientation. The board should drop in without any pressure required.

Step 12: Close the shell halves

Align the front shell half onto the back. The locating pins and receiver holes on the two halves will guide correct alignment — again, no force needed. Press them together gently until you feel them seat, then check all edges are flush. Pay particular attention to the corners and the connector end of the cart, which can sometimes gap slightly if the shell has any warping from heat damage.

Step 13: Refit and tighten the screw

Refit the Gamebit screw and tighten it clockwise. Tight means snug — not cranked down hard. The screw threads into a plastic boss, and it is entirely possible to strip the threads if you overtighten. You want the shell held firmly with no movement or flex when you press on it, but you should stop turning the moment you feel resistance. If the shell halves are still slightly gappy after the screw is fully tightened, the issue is probably warping in the plastic, not insufficient torque.

Step 14: Test the cartridge

Before you declare victory and file the cart away, test it in your console. Power off the SNES fully, insert the cartridge, and power on. A properly cleaned cart should boot on the first attempt. Watch the startup sequence — a PAL SNES shows the colour logo screen before loading the game. If the cart boots cleanly to the title screen, you’re done.

If it shows a grey screen, power off, remove the cart, check the console’s own slot connector (which can also be dirty — we’ll come to that), reinsert, and try again. If it consistently fails to boot after cleaning, see the troubleshooting section below.

Cleaning the SNES Console Connector: The Step Most Guides Skip

Here’s something that frustrates me about most cartridge cleaning guides: they treat the cartridge contacts as though they exist in isolation. They don’t. The cartridge contacts interact with the console’s edge connector, and if that connector is dirty, corroded, or damaged, you will continue to have problems no matter how perfectly you clean the cartridge.

The PAL SNES edge connector is a leaf spring design — 62 pairs of metal contacts that press against the cartridge board when you insert it. These contacts can become tarnished, bent inward slightly from years of use, or clogged with debris from repeated cartridge insertions. They’re harder to clean than cartridge contacts because you can’t disassemble them without tools and a more involved process — but you can do a reasonable job without opening the console.

Power off the console completely and unplug it from the mains. With the console powered off and unplugged, use a can of compressed air to blow through the cartridge slot — this dislodges loose dust and debris. Then, dampen a thin lint-free swab with IPA and carefully insert it into the slot, running it along the contact rows. You’re trying to reach the internal leaf contacts; a standard cotton bud is usually just about the right width for this if you flatten and angle it slightly. Make several passes. This won’t deep-clean the slot, but it will address surface contamination and is safe to do regularly as maintenance.

For a proper internal console slot clean, you’d need to open the SNES — which requires the 4.5mm Gamebit driver — and clean the slot contacts directly. That’s a more involved guide in its own right, but the principle is the same: IPA, lint-free applicator, gentle strokes, complete dry before powering on.

Troubleshooting: When Cleaning Doesn’t Immediately Fix the Problem

Sometimes you do everything right and the cart still won’t boot reliably. Don’t panic. There are several possible causes beyond dirty contacts, and most of them are diagnosable.

Cart boots inconsistently — works sometimes, not others

This is usually a console slot problem rather than a cartridge contact problem. The leaf spring contacts in the SNES slot weaken over time with heavy use and stop making reliable pressure contact with the cartridge. Classic symptom: the cart works if you hold it slightly to one side, or if you apply very gentle upward pressure to the bottom of the cart while it’s inserted. If this describes your situation, the console slot needs attention — the contacts may need to be carefully bent back outward to restore spring tension, which is a job for someone comfortable working inside the console.

Grey screen regardless of which cartridge you insert

This points to a console fault, not a cartridge fault. Before you assume the worst, clean the console slot as described above and test with multiple cartridges you know work. If none of them boot reliably, the issue is with the console. Common culprits on a PAL SNES of this age include failed electrolytic capacitors on the main board (a cap replacement job) and faults with the CIC lockout chip. Neither is unfixable, but they’re hardware repair jobs, not cleaning jobs.

Cart boots but scrambles or crashes during play

If the cart boots to the title screen but crashes, scrambles graphics, or freezes during gameplay, the issue may be the SRAM or the backup battery rather than the contacts. This is particularly common with carts like The Legend of Zelda: A Link to the Past or Super Metroid, which rely on battery-backed SRAM for save data. A dead or leaking backup battery can cause instability that mimics a dirty contact issue. Check the battery. If it’s the original 1990s battery, it’s probably dead — CR2032 replacement and resoldering is straightforward.

Contacts look clean but cart still won’t boot

If the contacts look genuinely clean under magnification but the cart won’t boot, examine the contact strip more carefully for continuity issues. Use a multimeter in continuity mode to check that the contact pads actually connect through to the ROM traces on the board. Lifted or cracked traces — which can happen from physical damage, battery acid corrosion, or just age — will prevent boot regardless of contact cleanliness. Lifted traces can be repaired with conductive silver epoxy or by soldering a fine wire bridge, but that’s a more advanced repair.

Contacts were stripped of gold plating during cleaning

If you used excessive pressure with the fibreglass pen or the wrong abrasive and have visibly stripped gold plating from some contacts — you can see silvery nickel or reddish copper rather than gold — those contacts will now oxidise much faster and may have marginal connectivity. You have a few options: apply a thin coat of gold contact restoration fluid (products like Stabilant 22 can improve electrical contact on compromised surfaces), or accept that the cart will need more frequent cleaning. In severe cases, PCB gold re-plating is possible but impractical at home.

How to Store PAL SNES Cartridges After Cleaning

Cleaning contacts and then storing carts badly is a waste of your effort. Oxidation will return — the question is how fast. Storage conditions make an enormous difference.

The worst things for SNES cartridge contacts are humidity, temperature fluctuation, and airflow carrying atmospheric pollutants (sulphur compounds in air are particularly good at tarnishing gold alloy contacts). A loft is essentially the worst possible storage environment: hot in summer, cold in winter, sometimes damp, often full of airborne particles from insulation materials.

Ideally, store cartridges at stable room temperature in a low-humidity environment. Dust sleeves — the thin plastic outer sleeves that were sold with many PAL carts and are now readily available as aftermarket items — make a real difference. They don’t create a sealed environment, but they significantly reduce dust accumulation in the connector slot. A dry, dark shelf in a bedroom or living area is genuinely much better than a loft box. If you’re storing a collection long-term, silica gel sachets in storage boxes will absorb ambient moisture and slow oxidation significantly.

After cleaning, a very light residual coat of DeoxIT D5 on the contacts (applied as described, with the final heavy IPA wipe omitted) provides mild oxidation protection that can extend the time between necessary cleanings. This is exactly what professional AV technicians do with XLR and phono connectors before long-term storage — it’s the same principle.

How Often Should You Clean PAL SNES Cartridge Contacts?

The honest answer is: when the cart fails to load reliably, or when you can see visible discolouration on the contacts. Not as a scheduled maintenance task on a fixed calendar. Over-cleaning is a real thing — every time you clean the contacts, even with the gentlest method, you’re removing a microscopic amount of material. The gold plating is thin. Cleaning it every month for no good reason will eventually cause as much damage as never cleaning it at all.

If a cartridge boots reliably every time you insert it, leave it alone. If you’re buying a new-to-you cart from a car boot, charity shop, or eBay, clean it before first insertion as a matter of course — not because it definitely needs it, but because you don’t know its history and you want to start from a known baseline. Cleaning before you play is also just good practice for protecting your console’s slot contacts from transferring contamination from a dirty cart.

A cart that you’ve cleaned properly and stored well should not need cleaning again for several years under normal play conditions. If a cart seems to need cleaning every few months to maintain reliable loading, the problem is likely the console slot rather than the cartridge — the slot’s leaf contacts are causing friction that deposits fresh contamination on the cart every time it’s inserted and removed.

Pro Tips From Experience

These are things I wish I’d known before I started cleaning carts, learned either through my own mistakes or through watching other people make them.

  • Number your screws if you’re doing multiple carts in a session. The Gamebit screws from different cartridges look identical but they’re not always interchangeable — thread depth and pitch can vary slightly between manufacturers, especially on third-party PAL releases. Keeping each screw with its original cart prevents annoying misfits on reassembly.
  • Don’t clean carts with the board still in the shell. I’ve seen guides that recommend wiping a Q-tip through the connector slot of a closed cartridge. This does almost nothing useful and risks pushing debris further into the shell where it can sit on the board surface. Open it. Do the job properly.
  • Check for battery leakage before every clean. It takes ten seconds to look at the battery holder and make sure there’s no white crystalline residue spreading across the board. If there is, that’s a more urgent job than contact cleaning — battery acid will eat PCB traces within months.
  • IPA temperature matters slightly. Cold IPA (straight from a garage in winter, for instance) evaporates more slowly and is marginally less effective as a solvent. Room temperature IPA works better. Not a critical factor, but worth knowing.
  • Photograph the board before you do anything. Takes five seconds, takes up almost no space on your phone, and is invaluable if you accidentally disturb a component or need to check what something looked like before you started.
  • DeoxIT D5 and IPA are not interchangeable. DeoxIT works on oxidation chemistry. IPA is a solvent that dissolves surface contamination and oils. Use both in sequence for best results on oxidised contacts — IPA first to remove loose surface contamination, then DeoxIT for the oxidation, then a light IPA follow-up. Using only one or the other gives you an incomplete result on anything beyond light cleaning.
  • Don’t insert a cleaned cart until the contacts are fully dry. IPA evaporates quickly, usually within two to three minutes at room temperature, but there are no shortcuts here. Inserting a damp cart into a powered console is unnecessary risk. Wait the full time, or gently warm the contacts with a hairdryer on the lowest setting from 20cm away to speed evaporation if you’re impatient.
  • The console matters as much as the cart. I spent a frustrated afternoon trying to get a PAL Super Mario RPG bootleg repro to work reliably on a heavily used SNES before realising the console slot was the actual problem. Testing known-good carts in the console before and after should be a routine step in any troubleshooting session.

A Note on Valuable PAL Carts and When to Stop

Some PAL SNES carts are genuinely valuable. Hagane: The Final Conflict regularly sells for over ÂŖ500 complete. Rendering Ranger: R2 has sold for over ÂŖ1,000 in complete condition. Even titles like Pocky & Rocky 2 or Demon’s Crest command significant prices. If you’re cleaning a cart worth meaningful money, you need to be more conservative than this guide’s default approach.

On a high-value cart, I would limit mechanical cleaning entirely and use only IPA and DeoxIT. I would use foam swabs rather than cotton. I would do multiple gentle passes rather than one heavy one. And if the contacts are severely corroded to the point where they’d need aggressive mechanical cleaning to restore — I’d seriously consider whether I was the right person to be doing this job, or whether the cart should go to someone with more experience and proper equipment. There is no shame in knowing the limits of your own skill level. Damaging a ÂŖ700 cart to save the cost of a professional clean is not a sensible trade.

For anyone who wants to get more confident with hands-on retro hardware, the best thing you can do is practice on low-value carts first. Buy a job lot of cheap PAL SNES sports titles from eBay — FIFA Soccer, NHLPA Hockey, Kawasaki Superbike Challenge, carts that cost ÂŖ1–ÂŖ3 each — and practice your technique on them. The skills transfer directly to the more valuable stuff once you’ve built the muscle memory and learned what “right” looks and feels like.

The Short Answer for People Who Just Want to Know What Actually Works

Since I know some people will scroll straight to the bottom: for the vast majority of PAL SNES cartridges with standard oxidation problems, the combination of 99% IPA followed by DeoxIT D5 will solve your problem. No mechanical cleaning required in most cases. Open the cart with a 3.8mm Gamebit driver, remove the PCB, wipe the contacts with an IPA-dampened lint-free swab using single strokes along the contact strip direction, let it dry, apply a tiny amount of DeoxIT D5 on a fresh swab, wipe, follow up with a final light IPA wipe, let it dry completely, reassemble, test. That process works on probably 85% of non-loading PAL SNES carts that have dirty contacts as the root cause.

The remaining 15% either need mechanical cleaning as well (follow Steps 8 and 9 above), have console slot problems rather than cartridge problems, or have a hardware fault on the board that cleaning won’t address. The troubleshooting section covers all of those. Don’t skip checking the console — it trips up more people than anything else in this process.

Thirty years is a long time for any electronics to survive. The fact that the vast majority of PAL SNES carts can still be rescued with a bit of IPA and a clean swab is genuinely remarkable — a testament to how well Nintendo engineered the contact system. Take care of them properly and they’ll outlast all of us.