if you want to clean something like that use Isopropyl Alcohol, the highest concentration you can get which is i think 95% or 90%.. don't just pour in on there... use a q-tip or cotton swab.. pour a little bit into the cap and just dip really quick to get some on it... alcohol evaporates really fast so it won't damage contacts and that kinda thing BUT it is still liquid and can still short out electronics if you arent careful so... BE REALLY CAREFUL!!! take out the battery and stay away from anything that looks like a capacitor.. oh and make sure its not that colored alcohol like the mint green color i see sometimes... it has additives for the color that leaves a residue.. use clear