This boiling method I've done a few times, but for my pieces I've found more economical ways to get the resin.

theres always a massive build up inside the cone, and 'peeling' it off with a small but sharp knife is alot easier, quicker and less messy than boiling.

for my pipe (the thing the cones sticks onto), i just pull it out of the bong, block up one end with the now clean cone, stick it inside a fan heater and let it incraese in temperature for about 5-10 minutes. this softens the resin. after picking up the extremely hot pipe with a tea towel horizontally, i bring it over to my tray and then turn in vertical. some dry crumbly resin should fall out. Then tap it a few times onto the tray and clumps and clumps of resin should just start falling out everytime you slam it down.

Roll that shit into a ball and smoke it like you need it.