I use acetone to clean my pieces. Yes, I know acetone is very flammable and bad for your lungs to inhale. The acetone cleans the glass on contact, and makes it clear again in five seconds. After that I let it run under water for a few minutes then let it dry overnight. You can't smell any acetone after you rinse, and I have been using acetone for years. I really recommend if you have acetone around the house, I do as I use it for many other things. I don't recommend using nail polish remover though. Although it has acetone in it, it may have other chemicals that leave a residue when it evaporates.


EDIT: BTW I only have a Bong and a Bubbler. I only clean the chambers with acetone when they get really bad. I clean the bowls under hot running water and a dental scraper tool weekly. I would use acetone to clean the bowls as I have before, I just don't b/c acetone is a bit expensive. Acetone evaporates very quickly and doesn't leave a residue so its fine to use for a bowl as well.