[metalalchemist]

It works, but if you live in the States, the best thing there is, apparently is Aves Apoxie sculpt Welcome to Aves Studio
As for poping the head, just submerge it in hot water for about 40 seconds and pop it out (I normally stick half a glass of water for around 2 minutes in the microwave, to let it "boil", then I stick the figure/part in). Other way, is using a hair dryer over the part, you just let it heat/soften enough to pop it out (like a minute or so)