Obviously cleaning solutions like rubbing alcohol and nail polish removers would work best, but if you just want it reasonably clean... hot water (the hotter the better, within reason) with some good grease cutting soap is good. What ever you do, rinse the fuck out of it, don't want any chemicals still in there when you light up.

I don't know if nail polish remover is a good idea, I personally use rubbing alcohol (proper name is Isopropyl Alcohol).