99% isopropyl alcohol is fine for circuit boards. It can damage labels and also dissolve glues, but it is otherwise safe to use.

Soap and water is also fine, though you want to make sure you dry the board completely. I usually use compressed air to blow things dry.

I echo the isopropyl alcohol method. Many retailers, at least in my area, don't carry 99%. However, some stores that sell beauty supplies do have it on the shelves. Or, you can order it online of course.

Most big stores like Walmart and many "dollar" stores do sell 91% on the shelves, and that's good enough for cleaning electronics as well.

Soap and water is indeed also good in this situation, but like Shponglefan said, make sure you completely dry the board.

On a side note, I've been looking at maybe getting an ultrasonic cleaning machine for those really hard to clean boards. They're not all that expensive, but I've just never pulled the trigger on one. I wonder how well one would work.

Shponglefan wrote on 2026-04-04, 22:33:

99% isopropyl alcohol is fine for circuit boards. It can damage labels and also dissolve glues, but it is otherwise safe to use.

Soap and water is also fine, though you want to make sure you dry the board completely. I usually use compressed air to blow things dry.

OK, here's take 1 with just IPA. Pretty good job of getting rid of most of the gunk.

There is still some brown/black stuff at the base of the MVA508 chip in the middle of the board, visible in the pic. Couldn't get a Q-tip down that far.

There is also some gunk near the CD audio connector on the board that didn't come off.

I may have to try to find new CD audio connectors and re-solder them on, I don't think I can get these clean. Now I need to figure out what they are called online to order them.

Might need a couple of passes, also an old toothbrush works well for agitating stuck on gunk

OK take 2 - after using a new toothbrush with IPA on it and really scrubbing, I have most of the gunk gone.

The only remaining problem is the CD audio 4 pin connectors at the top. Does anyone know what they are called online? I'll order a few new ones and desolder/resolder them onto the board. Thanks for the tips and confirmation that IPA was the way to go.

rjbrown99 wrote on 2026-04-04, 23:30:

The only remaining problem is the CD audio 4 pin connectors at the top. Does anyone know what they are called online? I'll order a few new ones and desolder/resolder them onto the board. Thanks for the tips and confirmation that IPA was the way to go.

https://static.cytron.io/download/usr_attachm … %20connetor.pdf

I don't know if they have an exact name but my local electronics store has them as "4 Pin 0.1in Straight Locking Header - 2.54mm Pitch - Single"

https://www.jaycar.com.au/4-pin-0-1in-straigh … single/p/HM3414

Thank you, that looks right! DigiKey has them in the US.

https://www.digikey.com/en/products/detail/w- … 0411121/2508466