How to Clean Used PC Parts: Step-by-Step Guide

Buying used PC parts in the UK is one of the smartest ways to build a capable machine without paying new-retail prices. But second-hand hardware arrives with history: dust, old thermal paste, oxidised contacts, and sometimes mysterious residue. Knowing how to clean used PC parts properly before installation is what separates a build that runs cool and stable from one that throttles or fails within weeks. This guide walks you through every major component — GPU, CPU, motherboard, RAM, case, and PSU — step by step.

Whether you just picked up a bargain bundle on Koukan or you have components sitting in storage, this process takes an afternoon and can meaningfully extend the lifespan of every part. Take your time, work methodically, and you will end up with hardware that looks and performs almost like new.

Safety First: ESD and Electrical Precautions

Before you touch a single component, set up your workspace safely. Electrostatic discharge (ESD) is invisible but can permanently damage sensitive silicon in an instant.

A £5–£8 anti-static wrist strap from Amazon UK is cheap insurance against destroying a £150+ GPU or CPU. Do not skip it.

Tools and Supplies You Need

You do not need specialist equipment. Everything below is available from UK retailers:

How to Clean a Used GPU

A used GPU is typically the most dust-laden component you will receive. Fans, heatsink fins, and the PCB itself accumulate years of debris. Follow this sequence:

Step 1 — External Dust Removal

1. Hold the GPU horizontally over a bin or outside. Use short bursts of compressed air — never sustained blasts — to dislodge loose dust from the fan shroud, heatsink fins, and PCIe connector area.
2. Hold fans stationary with your finger or a cocktail stick before blasting. Spinning fans at high RPM from compressed air can damage bearings and, in rare cases, generate back-EMF that could spike sensitive components.
3. Use the anti-static brush to sweep dust out of heatsink fin channels that compressed air cannot fully reach.

Step 2 — Fan Cleaning

1. Dampen a lint-free cloth or cotton swab with IPA. Gently wipe each fan blade on both sides to remove compacted dust and grease residue.
2. Check that each fan spins freely by hand. Any grinding or resistance indicates a bearing that is worn or gunked up. A drop of sewing machine oil on the centre spindle (after peeling back any sticker) can help, but replacement fans are often inexpensive.

Step 3 — PCIe Gold Contacts

1. Dip a cotton swab in IPA (not soaked — wrung to damp). Gently rub along the gold PCIe contacts in a single direction, not back and forth. Discolouration, oxidisation, or dried flux will wipe away.
2. Allow contacts to air-dry for a full 15 minutes before installation.

Step 4 — Thermal Paste Replacement

If the GPU is over three years old, or if you notice it running hot (above 85 °C under load), replacing the thermal paste is worthwhile. This requires removing the heatsink — check iFixit for your specific card model before attempting.

1. Remove the heatsink screws in a cross pattern to avoid warping the PCB. Most coolers use Phillips #0 or #1 screws.
2. Lift the heatsink gently. Old paste will often come away in grey or silver flakes.
3. Apply a small amount of ArctiClean 1 (or 99% IPA) to a cotton swab and clean all old paste off both the GPU die and the heatsink contact plate. Follow with ArctiClean 2 (or a clean dry swab) to remove any residue.
4. Apply a pea-sized (roughly 3–4 mm diameter) blob of fresh thermal paste to the centre of the GPU die. Reinstall the heatsink and tighten screws evenly in a cross pattern.

How to Clean a Used CPU

Used CPUs are generally robust but almost always arrive with dried thermal paste on the Integrated Heat Spreader (IHS). Cleaning this correctly ensures a good thermal interface with your cooler.

Removing Old Thermal Paste

1. Place the CPU face-up on an anti-static surface. Use a dry cotton swab to scrape off the bulk of any thick or flaky paste first.
2. Dampen a fresh cotton swab with IPA. Wipe across the IHS in straight, overlapping strokes. Replace swabs as they grey out. For particularly stubborn silver-compound paste, a brief soak with IPA and 30 seconds of dwell time softens it.
3. Finish with a final clean swab dampened in IPA to remove any remaining residue. The IHS should be uniformly metallic with no grey film.

Inspecting Pins and Pads

The critical difference between socket types changes what you need to check:

• Intel LGA (Land Grid Array — e.g. LGA 1700, LGA 1851): The CPU has flat copper pads; the socket has the pins. Inspect the CPU pads for scratches or burn marks. Inspect the motherboard socket under a desk lamp for bent pins — even one bent pin can prevent POST.
• AMD AM5 (LGA): Similar to Intel — pads on chip, pins in socket. Inspect the socket pins carefully using a bright light and a magnifying glass if available.
• Older AMD AM4 (PGA — Pin Grid Array): Pins are on the CPU itself. Check for bent, broken, or missing pins on the underside. Minor bends can sometimes be carefully straightened with a mechanical pencil (with the lead retracted) or a thin credit card edge.

How to Clean a Used Motherboard

Motherboards are complex and require a methodical approach. Work in good light so you can spot corrosion, burnt components, or debris in slots.

Dust Removal

1. Hold the motherboard vertically over a bin. Use compressed air in short bursts, working from the centre outward. Pay particular attention to the VRM heatsinks, chipset heatsink, and the area around the CPU socket.
2. Use the anti-static brush to dislodge any dust that is trapped in the dense fin arrays of VRM coolers or around capacitors.

Cleaning Expansion Slots

1. Fold a lint-free cloth to a thin edge and dampen lightly with IPA. Drag it gently along each PCIe slot and each RAM slot to remove debris and oxidisation from the contacts.
2. Cotton swabs dipped in IPA work well inside the M.2 slot channels. Insert gently and wipe along the length.
3. For the 24-pin ATX connector and CPU power connector headers, use a dry brush first, then IPA on a swab if contacts look dull.

Checking for Corrosion

Hold the board at an angle under a desk lamp and look for:

• Green or white powder on or around capacitors — this is corrosion and is a serious warning sign. Minor surface oxidation on ground planes can sometimes be cleaned with IPA, but extensive corrosion often means the board is not worth using.
• Burn marks or darkened PCB areas — these indicate a past electrical fault and the board should be avoided.
• Bulging or leaking capacitors — any capacitor that is swollen at the top or has residue around its base needs replacement or means the board should be retired.

How to Clean Used RAM

RAM is one of the easiest components to clean. The primary concern is the gold edge contacts, which can oxidise and cause boot failures or instability.

Gold Contact Cleaning

1. IPA method (preferred): Dampen a lint-free cloth or cotton swab with IPA. Wipe along the gold contacts in a single direction — do not scrub back and forth. The gold should look uniformly bright after cleaning.
2. Pencil eraser method (for stubborn oxidation): A clean, soft white pencil eraser can gently abrade surface oxidation from gold contacts. Rub in one direction very lightly, then follow up immediately with an IPA wipe to remove eraser debris. This method removes a tiny amount of gold plating each time, so use it sparingly.
3. Allow contacts to dry fully — typically 10–15 minutes — before installing.

When to Give Up on a RAM Stick

If contacts are deeply pitted, show black burn marks, or if the RAM fails MemTest86 after cleaning, the stick is not recoverable. DDR4 RAM in particular is inexpensive used — a replacement 8 GB stick can be found for £10–20 on Koukan.

How to Clean a Used PC Case

Cases accumulate dust in every crevice, especially around dust filters, fan mounts, and the cable management bay. A thorough clean takes less than an hour and makes a significant difference to long-term airflow.

Dust Filters

1. Remove all magnetic or slide-out dust filters. Most can be tapped over a bin to release the bulk of dust.
2. Wash with warm water and a drop of washing-up liquid — this is one of the few places water is appropriate. Rinse thoroughly and allow to dry completely (at least 2 hours) before reinstalling. Never reinstall a damp filter.

Case Fans and Mesh Panels

1. Hold case fans stationary and blast with compressed air. Follow up with an IPA-dampened cloth on each blade.
2. For mesh front panels or side panels, use compressed air from the inside pushing outward — this ejects embedded dust rather than compacting it further.
3. Wipe down the interior surfaces with a microfibre cloth dampened very lightly with IPA. The steel or aluminium interior can tolerate IPA without issue.

Cable Management Bay

The rear cable routing bay is often where lint, pet hair, and debris accumulate. Use compressed air to clear it, then a brush to sweep out corners. Cut any old zip ties and remove any orphaned cables from previous builds.

How to Clean a Used PSU

The PSU (Power Supply Unit) is the one component you clean from the outside only. There are no user-serviceable parts inside a PSU — and there are serious safety reasons for keeping it that way.

What You Can Do

1. Point the PSU fan-side down over a bin. Use compressed air through the fan grille to blow dust out of the interior. The fan will spin — this is fine at this stage. Work in short 2–3 second bursts.
2. Wipe the exterior casing with an IPA-dampened cloth. The metal housing can tolerate IPA without issue.
3. Clean the modular connector ports (if applicable) with a dry brush to remove debris, then a cotton swab with IPA for any that look corroded or discoloured.

What to Inspect Externally

• Check modular cables for fraying, burn marks, or melted connectors — replace if found.
• Listen and feel for fan wobble — a loud or wobbly PSU fan can indicate bearing wear.
• Check the cable labelling and ratings on the unit label (typically on the side). Cross-reference against your system power draw before use.

If you are unsure whether a used PSU is trustworthy, read our guide on buying used PSUs in the UK before installing it in your build.

Next Step: Test Before You Build

Once every component is clean, the final step before assembly is testing. Bench-testing outside the case lets you diagnose issues without disassembling a completed build. Our guide on how to test used PC parts covers everything from POST tests to stress-testing tools, so you can be confident in your components before a single screw is tightened into the case.

Not sure which components are safe to buy second-hand in the first place? Our guide to which PC parts are safe to buy used breaks down the risk tier for every component category.

Frequently Asked Questions