Shower, mild abrasive sink cleaner (creamy white stuff) and a soft nylon brush.

I spray everything off with Freon-TF to degrease and clean -- this usually gets 95% off. For the remaining gunk, a small stiff hog-hair brush and 90%+ IPA. For corrosion or oxidation, you'll need Texwipe swabs to clean up that.

Toothbrush can do wonders, I keep all my old ones for this purposes haha

I've seen people do all kinds of stupid sh*t to clean motherboards some of it is less bad than others. Best thing to use is use only distilled water if you are going to use water, because tap water has dissolved solids and minerals and other kinds of nasty junk in it. For alcohol only use the 99-100% pure technical grade, because all of the other ones contain other chemicals that will leave nasty white film over everything.

I use a paintbrush with the 100% alcohol i spray from a bottle, then I use distilled water in a spray bottle and I remove all of the alcohol and dirt left behind, i might repeat this step multiple times until im sure the board is clean, then when I am done i spray the board down with alcohol as it displaces the water and I set the board on a shelf next to a dehumidifier for 24 hours. 🤣

ultrasonic cleaner with isopropyl alcohol

Warlord wrote:

For alcohol only use the 99-100% pure technical grade, because all of the other ones contain other chemicals that will leave nasty white film over everything.

White film could be alcohol attacking the plastics, so it's probably best to avoid using any, if looks are of concern. As for water containing impurities, whatever is safe to drink is ok to wash your PCBs with. Any trace amounts of dissolved salts or carbonaceous rock won't be conductive when dry anyways.

dorkbert wrote:

ultrasonic cleaner with isopropyl alcohol

I've heard quartz resonators may break from ultrasonic cleaning, any comments on this?

an81 wrote:

Warlord wrote:

For alcohol only use the 99-100% pure technical grade, because all of the other ones contain other chemicals that will leave nasty white film over everything.

White film could be alcohol attacking the plastics, so it's probably best to avoid using any, if looks are of concern. As for water containing impurities, whatever is safe to drink is ok to wash your PCBs with. Any trace amounts of dissolved salts or carbonaceous rock won't be conductive when dry anyways.

wrong my dude, alcohol is 100% safe to use regardless of purity. However normal rubbing alcohol that people buy is denatured and is full of adulterants by law, thats why the highest you can buy at like the drugstore is 91% but most people use sh*t that is worst like 70%.... the residue or white film, it is due to dissolved impurities that make up that other 30-10%.

dorkbert wrote:

ultrasonic cleaner with isopropyl alcohol

Ultrasonic cleaner is like a last resort kinda thing imo becasue it can skullfu*ck motherboards that have nothing wrong with them, its what you do when your board doesn't work or has severe damage to it, becasue it cleans under chips unlike using a toothbrush in that case you use distilled water and branson EC as a detergent. 103ml per 1 gallon of distilled water at 65 degrees Celsius 1 minute per side.

A toothbrush shouldn't be used since they're synthetic fibers which can generate ESD. You should be using a horse hair or hog hair stiff bristle brush with a wooden handle.

tootbrush is fine becasue its wet, and a wet toothbrush doesn't generate ESD. I somtimes think a toothbrush can do dammage though becasue its bristles are too stiff or you hit a component with the shaft.

Warlord wrote:

Best thing to use is use only distilled water if you are going to use water, because tap water has dissolved solids and minerals and other kinds of nasty junk in it.

I don't think regular tap water is bad for cleaning PCBs. I always use simple tap water with a bit of dish soap. Efficient and effective.
Can you explain why you think destilled water is better than regular water for this application? What's the practical problem with the "dissolved solids and minerals" in it and what "other kinds of nasty junk" are you referring to?

That experiment does not apply since you're not applying a current when cleaning your PCBs. (Are you? 🤣 ) Destilled water won't save you either when applying current.

Edit: I guess you realised that yourself since you removed the post. 😉

Na i removed the comment becasue I realized 2 things. 1 posted the wrong video and 2 I'm talking to someone that really doesn't care, that tap water can be corrosive, and that tap water standards vary from country to country.

Corrosive water.
https://drinking-water.extension.org/2019/08/ … orrosive-water/
List of accompaniments in tap water.
https://www.epa.gov/ground-water-and-drinking … ter-regulations
printed circuit board rinse water quality
http://pcbfab.com/rinse-water-quality/

1 Tap water, especially tap water mixed with detergents, should never be used for cleaning circuit boards. 

http://www.circuitnet.com/experts/70402.html

Tap water contains ions that are the result of dissolved solids. If you us it salts and residues get left behind. Over time, these confinements will react with the air and cause corrosion in metal surfaces.

1Distilled water: When you use water to clean a circuit board, you must make sure it has no contaminants. The ions in regular water have conductive properties that degrade electronics. Meanwhile, distilled water has no contaminants or ions that cause damage.

https://www.mclpcb.com/pcb-corrosion/

This women City tap water.
https://youtu.be/YxRTUrfexJQ?t=453

Warlord wrote:

tootbrush is fine becasue its wet, and a wet toothbrush doesn't generate ESD. I somtimes think a toothbrush can do dammage though becasue its bristles are too stiff or you hit a component with the shaft.

Depends on your cleaning solution and method. If using isopropyl alcohol, DI/RO water, or another dielectric cleaning solution, those are not conductive (or approximately <10 μS.m−1 conductivity), so using a brush-dipping method (IPC typical/recommended for rework application) would still generate ESD despite the bristles being soaked. You would really need to totally submerge the component to have enough dissipation. It is a lot safer just to spend the $3 on a natural bristle brush. Any rework standard including IPC guidelines have you using a natural bristle brush for this reason.

If we're all interested in preserving retro hardware, it is best to clean and handle components the proper way.

That's a fair point, i suppose it its totally possible to ESD shock a chip on a PCB with a toothbrush that was soaked in alcohol. I have just never heard of it happening. Or the chance of that happening is extremely low and would require your toothbrush to be positively charged before you dipped it in alcohol or water or whatever. ESD is caused in low humidity environments, and in high humidity environments the moisture in the air forms a thin protective “film” on surfaces that serves as a natural conductor to dissipate electric charges, if something is just flat out wet we are talking 100% humidity a toothbrush shouldn't generate ESB becasue the water will increase in return current, which is the current that opposes a charge buildup.

Source
https://www.gndzero.com/techdocs/questions/Hu … on%20042205.pdf

As far is IPA is concerned.
IPA liquid was able to remove both positive and negative
static charges equally well.

Source
https://www.google.com/url?sa=t&rct=j&q=&esrc … caUUWwFDhhVw7bE

True, it is quite rare that something gets flat out killed by ESD unless total carelessness takes place in a dry environment. Usually ESD does latent damage where it manifests later on in the life cycle of the component, ending in premature failure. ESD will damage traces and junctions in microchips that would have normally lasted a human lifetime easily, but instead with the damage may fail anywhere from the next power cycle to a few years down the road.

I prefer paintbrushes, over toothbrushes, which should easily find natural ones at hardware stores. for several reasons. tooth brush might still be the go to brush for trying to clean up corrosion in some spots. I recommend using baking soda mixed with distilled water to clean corrosion with, especially from batteries on old motherboards.

Thank you for providing some sources. However I do not think they really make a strong point on explaining why tap water would be inadequate for cleaning PCBs on a hobbyist's scale:

First you provide two links on water quality and corrosive properties of tap water.
Yes, I know the complexion of tap water differs greatly regarding both mineral content and amount of small particles depending on factors like origin, treatment and plumbing. I also know water is always corrosive. Sea water is corrosive, rain water is corrosive, tap water is corrosive, distilled water is corrosive and de-ionised water is also corrosive. Still my claim is: When submerging PCBs in any kind of water that you would expect to come out of the tap in the first world for short periods of time this is negligible. At room temperature those processes are very slow. Constant exposure to air humidity over decades does a much better job at corroding metal on PCBs than a few minutes of tap water rinsing. Destilled water will likely cause less corrosion on PCBs, but is that difference relevant in our application? Both copper and tin (which together with gold make up the vast majority of exposed metals on PCBs) form a protective oxide layer on their surfaces that very effectively hinders further corrosion. I have never seen any proof there's a relevant difference regarding corrosion when cleaning PCBs with tap water vs. destilled water. Even chemists told me it probably doesn't matter.

The next articles are focussed on adequacy of (tap) water in cleaning PCBs. Though they do not really elaborate either, mostly stating that tap water will leave something on the PCB after drying from evaporation (ok, but what and what effect does it have/why is it bad?) and should not be used. I am actually interested in finding out what actual problems might arise from the (definately existent and from my pov completely irrelevant) amounts of minerals that might deposit on a PCB after thoroughly rinsing it with tap water. Both articles are not really interested in the effects of corrosion from submerging the PCBs in water which leads me to believe they also believe the effect is irrelevant at tap water ion levels.

The first article you present mostly deals with a lagre scale production point of view: Will residuals from various cleaning/rinsing solutions hamper further production steps? (The article gives drag in from alkaline cleaning agents contaminating an acid copper plating bath as an example.) Will the solution clean the PCB quickly so production can move quick? Will the solution dry quickly so production can move quick? All those questions do not apply to us hobbyists cleaning PCBs on a small scale.

My experience is identical to what's quoted in your second article:

We have been reworking circuit boards for the past 30 years. After solder touch-up we remove flux residues with ordinary alcohol, then clean with soap and water. We then dry each assembly with a blower. We have never encountered issues with microprocessors.

Btw. in the first response to that question the same article/discussion states distilled water wasn't good enough either.

In terms of precision cleaning, neither tap water nor distilled water are sufficiently pure to handle the job as both are contaminated, to greater or lesser degrees, with minerals and organics. So if you want to use water, you must jump to DI-water.

And I really think we can agree that as hobbyists we can safely disregard that position.
The second article/expert panel discussion also talks about process speed and reusability of water and besides that mostly focusses on wether water is sufficient to remove production residue like flux. Again this article/discussion is from an industrial pov. As hobbyists we're mostly dealing with dust and small amounts of organic fats/oils stuck on PCBs. Those can easily be removed with tap water and dish soap. With a good rinse the dish soap is removed as well. Blow it off with a compressor and you're golden. The amount of water and work used here would be totally unacceptable in production scale but for some dude tinkering with electronics it's not much of a problem.

The third article does little to enlighten on why destilled water is to be preferred when cleaning PCBs on a hobbyist's scale. Again my assumption and experience is: Corrosion on materials regularly found on PCBs from a few minutes of exposure to tab water will not be significantly different from the same amount of exposure to destilled water.

Meanwhile, distilled water has no contaminants or ions that cause damage.

Is plainly wrong. De-ionisied water contains no ions. Destilled water still has lots of them left. De-ionised water will very quickly solve ions from any metal it comes into contact with, again becoming regular conductive water capable of acting as an electrolyte.

The video you posted can safely be disregarded as an uneducated esoteric's approach to determining water quality. She actually scrubbed her water heater for residue that has come out of solution after heating and thinks it would have harmed her in any way because now she can see it. Again yes, there's more ions in tap water than destilled water, no argument. But does it matter?

I guess you can see how my serious question boils down to what actual difference there is when exposing PCBs to regular tap water vs. destilled water over a few minutes and how this difference will affect behaviour of electronics after drying.

And thank you from removing that part about me making intentionally bad posts here. I'm not trolling, I'm interested in finding out if there's any truth to the much heard saying of "only use destilled water for cleaning electronics" because I like to know if and how I'm doing something wrong as long as I actually am.
I think we're all friends here and we're all in the same boat. 😎

I too prefer paintprush to toothbrush ..
1/2 inch is preferable and easy to handle ..
Trim down the bristles to about 2 to 3 cm from the collar ..to make the bristles effectvely stiffer where the are closly packed.
And I can confirm that after 50 years in the TV repair trade I have never seen anything damaged by ESD if precautions are taken.
Simply grab hold of a water tap first to ground yourself briefly before handling anything sensitive.
neutralize any corrosion (leaky batteries etc) with pure white vinegar.
Tap water is fine in most cases and even I've put pcbs in a dish washer before now ..(without salts of course) ...just soap.
Make sure the pcb is thorouhly dry before applying power ( pop on a radiator or use a hairdryer)and use alcohol after washing to remove loosened grime /flux.
Totally volatile ..and evaporates without residue.
Sonic cleaning is good but only very expensive units will have the capacity for large boards.
rgds
VS