Try simple green. That usually cuts through grime pretty well. Walmart carries it, usually somewhere around the automotive section.

I use Mean Green (usually found in Dollar Stores) and an old toothbrush. Let the Mean Green set a minute, give it a light scrub and then rinse and blow dry with compressed air. Or drip dry if you don't have a compressor.

Put it in your wife's dishwasher. And yes I am completely serious.

super clean will take that right off. just rinse it real well and make sure you let it completely dry before applying power.

I have used alcohol and q tips w/good results. Make sure it dries and don't get any on the display itself.

Someone else told me this as well. I wonder if it works?

I've washed lots of boards with no harm. I always use no detergent, and no electric heat cycle.

Mean Green or Super Clean. Use a toothbrush if necessary. Rinse with water. Follow up with an alcohol rinse. I usually place them on a towel with a fan blowing on them for ~30 min.

It only hurts if you try to turn it on while it is wet or if there is residue left behind that would cause a short. Otherwise, water won't harm it.

I use ultrasonic cleaner for dirty boards

I agree with the dishwasher. I owned a business that has repaired thousands of PC boards from electric lift trucks over the years and the dishwasher was my best tool. I used to use a "vapor degreaser" machine that utilized Freon as a cleaning media, but since has been outlawed.

Dishwasher works well, but I would remove the IC's first, clean under them, then install a socket. Many times, corrosion forms under the IC and you'll only trap it if it's not cleaned properly. Plus, it gives you a chance to inspect copper traces that may have been acid damaged and hidden under the chip.

Also a real good tool is one of those electric "Dental Water Pic" machines that induces a high pressure water jet that can safely remove dirt and corrosion, and clean out connector terminals easily.

Set your oven to warm, to hasten evaporation of collected water. It only takes a few minutes to dry. Or use a heat gun on low.

I have not tried dishwasher but have been warned to NOT use the drying cycle.

I use the ultrasonicator for any boards with only sealed parts. After cleaning rinse with water, then with alcohol, then blow dry VERY well and let sit.

some of the pros reccomended this and now I use it.

Alcohol and a very soft tooth brush. Can't go wrong.

This may prove useful:

http://wiki.arcadeotaku.com/w/PCB_Cleaning_101