Some friends of mine boil their pieces as a method of cleaning. I personally use the isopropyl-salt-plastic bag method, which works very well and is cheaper than Formula 420 or various other cleaning solutions. These friends of mine boil their pieces and filter the remaining water through coffee filters I think and what they are left with is all the resin from the pipes. They then put this into the freezer, which hardens it. After it comes out of the freezer, you can smoke it. I don't really like the taste of rez, and I know there's a lot of the bad stuff left in it, and not much THC, but if you're in a bind and don't have any buds, it'll work. Most of the time smokin rez is considered an act of desperation or whatever, but to each its own I guess.