[NoodleChow]

hmmm.... try dipping them in hot microwaved water or keeping em under a relatively hot lamp till they're a little pliable. then let em cool off and pop em back on. basically hot water should "reset" the plastic since it was likely warped a bit due to the packaging. works the same for legs that fall off a lot. otherwise a little bit of glue or nail polish and letting it dry to bulk up the joint should work too.

those comic pack figures that are basically the wolverine origins figures can sorta pop apart at the torso. like a bar with a ball and socket in there. though it depends, i'd cracked a wolverine apart using force but didn't heat anything up to begin with. so prolly add heat. some of the figures i have popped apart with relative ease, others won't budge. but essentially, add glue or nail polish and let it dry on the ball or socket area if you manage to get em apart.