I used boiling water to clean my bong, and it cracked it in half right on the neck.

I bought the 420 cleaner, and that stuff is great. Put a little in a zip lock bag with your pipe, swish it around for maybe 30 seconds, then rinse it with warm water. It removes everything.
Nancy007 Reviewed by Nancy007 on . Care and cleaning of your glass pieces Hello all, I just wanted to post up a thread discussing pipe maintenance. There used to be a resin cleaning guide, but I and others feel that smoking resin really isn't a legit medical method- Old resin inside your pipe is not really something desirable to smoke, even though, yes, it does serve in a pinch. I'm more interested in methods of getting resin buildup out of your pipe so that your smoking experience is as pleasant and healthy as possible. A clean bong is a happy bong! Rating: 5