I would use rubbing alcohol... will not strip off lettering but will do a great job cleaning. Will also evaporate fast and not leave residue or anything of the sort!
Don't lick it! Lol. I have some Bausch and Lomb Sight Saver tissues that have alcohol that work well. I wouldn't use any paper products on the screen because they can scratch.
Posted from my CrackBerry at wapforums.crackberry.com
Make sure you are using alcohol that is at least 70% Isopropyl alcohol. Clean it with a cotton swab or soft bristle brush, like a baby toothbrush. If you can, use a can of compressed air to blow it out immediately after the cleaning rather than letting it evaporate. When the alcohol evaporates, it does not take the dirt and grime with it, it merely settles somewhere else. I would also recommend eye protection and possibly a dust mask if you use the compressed air.
This is how we clean electronics in the Air Force, and it works very well. Good luck to you.
A BB is a closed case, meaning it's not like a PC. You have no idea what particles are lying in there and you could end up forcing something bad further into the phone that might affect the circuits.
Just wipe the keys with whatever except acetone. Alcohol q-tips, any kind of wipe be it alcohol, bleach, whatever will be safest.