I clean my pieces the same way and usually boiling them a couple of times works for me. Are you getting a nice clean piece when you're done or is there still some resin? Usually after boiling mine I use a towel to hold the piece while it's still hot then unbend a paper clip to scrape some of the resin out while it's still soft. Then I turn my sink hot and run water through the piece while using the paper clip at the same time. After that I use basic dish soap and clean it up just to get the sticky stuff off the outside that also seems to get rid of that alcohol flavor.

Don't really know if that helps but I can't sleep and figured if I've been on this site for a couple years so I should start posting.