What i do when my bowl has a lot of resin is I heat up the bowl with a lighter, then use a paperclip to get out all of the resin. Then i roll all the resin back up into a ball and smooke it out of my piece. Resin is pretty ditry and tastes like shit, but if your dry...Its good to smoke. Then if you want to 100% clean your pipe place it in a mixture of rubbing alcohol and salt. That shit will lift all of the leftover resin right off the piece. It will look brand new.