another recommendation for formula 420.

works great and it's fast. i'm sure salt/rubbing alc. would do a similar type of cleaning .. but it's easy to just go buy a bottle and have it always ready to clean the bowl or the whole bong.

and i've cleaned my bong at least 10+ times and i'm on the same bottle of cleaner .. you really only need a little for it to work .. i've let my bong go for a week without cleaning and just a quick squirt of the stuff gets it like new.