Cleaning electrolyte from PC board

[Joyce]

What is the best way to clean electrolyte from a circuit board? A cap exploded and left a mess. I'd like to save the board if possible. Thanks for your help.

[shadow]

I think I have used methylated spirits before with a toothbrush (or at least a cloth).

[c_hegge]

You could probably use a cotton bud as well

[Huckfinn]

For many years now I have successfully used hot water and different sizes of bristle brushes. Use compressed air to dry the board. When compressed air is not available, I drain and tap as much water off the board as possible, then finish drying it with a hair dryer set to a low or medium heat setting, and a high blower setting. This technique even works well for circuit boards that contain components that could be adversely affected by water [moisture] entrapment, provided that you are careful and use some caution. Motherboards are in that category of boards that have parts that can be subject to moisture entrapment. Tip the board so the hot water runs away from the component that might trap moisture under it. If the mess you are cleaning up happens to be right by a component that is of concern, clean carefully and dry thoroughly. Most motherboards do have some components that are of some concern. Before cleaning, unplug and remove ram sticks, CPU and cooling fan unit, PCI and other slot plug-in cards. If possible, avoid getting water under chips, and into sockets. If it happens, just dry thoroughly. The significant issue is that if because of not-so-thorough drying, moisture remains, for example between a surface mount chip and the board, under power, electrolytic corrosion [greenish fuzz] could occur. Thorough drying will prevent this. [Note that electrolytic corrosion due to current flowing on a wet PC board is a bit different from corrosion due to spilled electrolyte from a capacitor that is leaking. Electrolyte spilled from the inside of a capacitor with some sort of case or seal rupture is corrosive both with and without current flow! ]. Also keep in mind that hot water poses much less of a risk to a board [after proper drying of course] than alcohols, solvents, cleaning solutions, etc. and it is better to work a bit to wash and dry a board, rather than risk all of the nasty corrosion that is almost always sure to occur when capacitor electrolyte leaks on the board surfaces and on to parts like chip leads. Keep in mind that leaked electrolyte can and often does eat all the way through some of the small copper runs of the circuit board. The solder resist protective lacquer looks like it will nicely protect the copper lines [runs] from electrolyte corrosion, but actually the electrolyte softens the lacquer and gets under it to attack the copper runs. The protective lacquer on motherboards can be any number of different transparent colors. The common ones are green, amber, yellow, blue, and red. Water won't affect this lacquer, but leaked capacitor electrolyte will demolish it.

Some additional notes of clarification:
Most any type of electrolyte [fluid] is corrosive to metal, including part leads and copper foil circuit traces [runs].

Electrolytic corrosion is a term that is used to describe corrosion that occurs due to an electrolyte coming in contact with metal. Electrolytic corrosion also occurs when just water comes in contact with metal at the same time as there is a current flowing in the metal circuit, due to impurities in water, some current flows in the water itself. [Current does not flow in really pure distilled water]. Water contacting metal with no current flow also facilitates corrosion, but at a much slower rate.

Hope this all helps.

Huck

[Topcat]

always used a fine wire bristle brush, always worked like a charm.

[JayArr_BC]

Put it in the dishwasher, set it for NO HEAT on the dry cycle (so the big heater coil doesn't come on at the end of the rinse cycle)

It'll come out looking like new.

You can dry it quickly with compressed air, or a hair dryer, put it in the oven at 200 degrees for an hour or just leave it on top of your fridge for a day or two.

I've been doing this for more than 10 years - no problems.

Jeff

[Evil Lurker]

Scrubbing bubbles shower cleaner. I swear by it.

Good for cleaning spilled electrolyte, cig smoke tar, dust, crispified centipedes and other insects, and carbon.