>>7769960I've popped a lot of heads off, and It's pretty hard to damage a rubber head. The worst that can happen is maybe a small little tear around the ring, and that's only if the head is really old.
Besides it's not the head you need to worry about. Messing up a dolls hair style while trying to pop the head off is something to keep an eye out for, but what you really need to worry about is not breaking the neck of a MtM body while popping off the head. I've had a few accidents in my day. The older the doll the more dangerouse it becomes as the plastic gets a brittle when it ages.