If you're not interested in the resin for smoking when desperate times call for desperate measures, use rubbing alcohol by putting it in, swishing it around especially if it's a bong, and once it comes off the pipe rinse it out. This works really quickly compared to boiling.
If you use resin, boil and use coffee filters to catch the resin and allow to dry. When it comes to boiling glass, let the glass pipe heat up with the water. I've found that it's not necessary to let it cool down with the water, but don't put cold water on hot glass... my windshield still wears the scar of the day I suffered from a severe blonde moment. The sound of it cracking in half still haunts me... Anyway, just be real cautious when handling a hot glass pipe and not letting it hit anything. Set up a towel to put it on when you're done boiling.