milk on PCB

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Any ideas how to remove encrusted milk off small SMD components? My darling 17 year old managed to pour a glass onto her laptop which oozed through the keyboard onto the motherboard. Hit around the power management circuits. So by the time I got hold of it had set into nice furry deposits on tiny SMD components. I don't have a dishwasher which I know is the usual in this case and my handy spray can of flux remover isn't even making a dent so wondering what is next up the chart I can try? I know I have less than a 50% change of getting this thing back to life but have to try :)
 
You can usually buy isopropyl alcohol (IPA) at the pharmacy. Beware that rubbing alcohol is a low concentration of IPA and is not as useful for cleaning electronics. You'll need the highest concentration you can get.

At an electronics store, you can usually find horse hair brushes intended for flux cleaning. I'd get one of those and a can of flux cleaner.

Clean the PCB with IPA first. Then flux cleaner. Then wash with IPA.

If you don't have a horse hair brush, a toothbrush can work. Just beware that many flux cleaners contain acetone which will very likely dissolve the bristles on the toothbrush and make an even bigger mess.

Tom
 
Milk solids are water soluble and not solvent soluble.
brushes.jpg
Use an artists brush like those above (bristles cut square and shorter) and scrub the affected area, quickly dry the brush in cloth or tissue, and then use the brush to draw up the liquid in strips/stripes.
Do this process twice or more to remove all traces of organics/solids.

Repeat the above process with Isopropyl, and then 'cook' with a hair dryer to evaporate all solvent remnants.

Close inspection may reveal solder joints that are already electrolysis/deeply corroded.
Apply liquid flux and resolder these joints and then IPA clean and reinspect closely.

This has been my standard coffee/beer/whiskey/cola/milk/water damage repair method since forever, works for me.

Dan.
 
Espresso Steam

I have had success loading distilled water into an espresso maker and blasting a PCB with the steam wand. Cleaning a PCB with alcohol can sometimes just smear certain types of solder flux around on the board and not remove it, spreading slightly conductive gunk everywhere. Board manufacturers usually clean with de-ionized water wash, so emulating that is usually your best bet.
 
I have found that warm water flowing on the board removes many things. Even a little bit of dish soap in water. A little soft brush action is a good idea too.

Alcohol absorbs water into itself readily, and in biology labs and such places, they even use it as a drying agent after water washing glassware. And in some places, ether after alcohol.

Isoprop alcohol from the pharmacy usually comes in strong - like 95% - and dilute. I only buy the strong, since I can always dilute it if need be. But either should work here. And they are real cheap. NO need for reagent grade or lab quality stuff, we are just cleaning with it. Very useful around the shop.
 
Cheap toothbrushes work wonders on electronics, they scrub off all the gunk very easily.

Milk isn't super terrible in a laptop, all the ones I have had to deal with at work came back to life after a thorough wash and scrub in the affected area. Keyboard may not survive though but they aren't very expensive and meanwhile waiting for replacement you can use an USB keyboard or enable "on-screen keyboard" in accessibility settings.
 
I've used industrial steamers in the past to clean PCBs but stopped using them after I learned firsthand how potentially damaging it can be to ESD sensitive parts.

One day while cleaning a CRT monitor driver PCB, board on one hand and the steam wand on the other hand, I noticed that the neon lamp on the board was glowing bright orange. It appears that the jet of steam coming from the wand was generating enough electric charge to light up neon bulb. Neon bulbs ionizes at around 90V. One can imagine the how much electric charge is really being built up on the board during this process.
 
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Removed the motherboard to fit the new one this evening. Turns out there was milk gunk on the underside as well. I thought about another clean but decided against it as would incure additional cycles on the ribbon connectors which I have a pathalogical hatred of after years of fixing nintendo DS for the kids. So part of me still feels bad for wussing out, but laptop works and I can get back to interesting audio projects :)
 
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