How to clean thermal paste off a CPU (and the cooler) without damage

Step by step: how to clean thermal paste off a cpu

Safety first. Shut the computer down and unplug it before you touch anything inside, and touch a bare metal part of the case to discharge static. Isopropyl alcohol is flammable: keep it away from flames and let it evaporate fully before you power on. Work with the window open, and wash paste off your skin with soap and water.

1. 1

   Shut down, unplug and ground yourself

   Shut the computer down, switch off the power supply and pull the power cord. Press the power button once to drain leftover charge, then touch a bare metal part of the case. Work on a clean, well-lit table.

2. 2

   Warm the paste, then lift the cooler

   If the PC was just running, the paste is still soft, which makes the cooler easier to remove. Loosen the cooler screws a little at a time in a cross pattern, then twist the cooler gently side to side before lifting. Never pry it straight up, because on some sockets a stuck cooler can pull the CPU out with it.

3. 3

   Wipe off the bulk of the paste dry

   Use a dry lint-free wipe to lift most of the old paste off the CPU’s metal lid and off the cooler base. Wipe from the edges toward the center so paste does not get pushed over the sides. You should see bare metal showing through after two or three passes.

4. 4

   Wipe with isopropyl alcohol

   Dampen a fresh lint-free wipe with 90% or stronger isopropyl alcohol; it should be damp, not dripping. Wipe the CPU lid in small circles until the gray haze is gone, switching to a clean part of the wipe often. Do the same on the cooler’s contact plate.

5. 5

   Clean the edges with a swab

   Dip a cotton swab in alcohol, squeeze out the excess, and run it around the edges of the CPU lid and any lettering where paste collects. If paste spilled onto the socket or the tiny components around the CPU, use a barely damp swab and light pressure, and pick any loose cotton fibers off with tweezers.

6. 6

   Soften dried paste instead of scraping

   Old paste can dry into a crust. Lay an alcohol-damp wipe over it for a minute or two, then wipe again. If a little is still stuck, push it off with the edge of a plastic card, never a metal blade.

7. 7

   Let everything dry

   Give the CPU and cooler 2 to 5 minutes to air dry. Alcohol evaporates fast, but 70% alcohol leaves more water behind, which is why the stronger kind is used here. Both surfaces should look clean and mirror-like or evenly matte, with no streaks.

8. 8

   Apply fresh paste and refit the cooler

   Follow your cooler or paste maker’s method; a small pea-sized dot in the center is the common one. Set the cooler straight down without sliding it, then tighten the screws a little at a time in a cross pattern. Boot up and check CPU temperatures in your BIOS or a monitoring app.

What should you use to clean thermal paste off a CPU?

Use isopropyl alcohol of 90% or higher, a lint-free cloth and cotton swabs. That is the kit Corsair lists for removing thermal paste, along with keeping the cloth only slightly damp and letting the alcohol dry for a few minutes before you reapply.

What if thermal paste got on the socket or pins?

Most modern thermal paste is not electrically conductive, so a smear on the socket area is a cleanliness problem, not an emergency, but it should still come off. The product page for Arctic’s MX-4 says it is not electrically conductive, unlike liquid metal compounds. Check your paste’s data sheet to be sure: Arctic’s MX-4 safety data sheet, for example, lists its contents (mostly aluminum powder in a silicone base) and advises washing skin contact off with soap and water.

• Take the CPU out of the socket only if paste is on its pins or pads. Hold it by the edges.
• On a CPU with pins (many AMD chips), brush paste out from between pins with a soft, clean toothbrush dipped in 90% or stronger alcohol, brushing along the rows so you do not bend them.
• On a CPU with flat gold pads (most Intel chips), wipe the pads gently with an alcohol-damp swab.
• Never touch the socket pins on an Intel motherboard; if paste is in there, a soft brush and alcohol only, then let it dry fully.
• Liquid metal compounds are conductive. If you used one, follow its maker’s cleanup instructions, since it behaves differently from paste.

How often should you replace thermal paste?

Replace it whenever the cooler comes off, and otherwise only when temperatures creep up. There is no fixed schedule; good paste in a desktop often lasts several years.

Signs it is time: the CPU runs noticeably hotter under the same load than it used to, the fans ramp up more often, or the old paste looks dry and cracked when you open it. Before you repaste, rule out dust, which is the more common cause of rising temperatures; our laptop fan guide covers clearing vents with compressed air. Laptops are harder to open, so check your manual or have a repair shop do the job if you are not comfortable taking one apart.

Mistakes to avoid

• Pulling the cooler straight up when the paste is cold, which can yank the CPU out of the socket.
• Using paper towels or tissues that leave lint in the new paste.
• Soaking the cloth so alcohol runs off the CPU onto the motherboard.
• Scraping dried paste with a knife or screwdriver and scratching the lid or cooler plate.
• Powering on before the alcohol has fully evaporated.
• Spreading new paste on top of old residue instead of starting from clean metal.