stripping paint of a helmet?

has anyone stripped an old paint job off a helmet?? or do you just sand it down and prime it?

i stripped down 2 helmets using acetone.

the master replicas helmet had no issues. the one made of smoothcast roto was 99% ok, but the keyhole area melted a little... i had already cut them out, so there wasn't much left back there. it was easy to fix, but there was some damage.

well the one i want to strip is i guess, casting resin "slush mold".