I've used Easy Off Oven Cleaner to strip Acrylic & Enamel paints (including primer) from my Pewter, Plastic & Resin figures with out any damage to the material. Use an old plastic coffee (Like Folgers) and place your figures inside, spray liberally with the Easy Off Oven Cleaner. Let them sit for a few hours (I've forgotten about pieces and left them for over a week w/out damage also) then run them under warm water and scrub with an old toothbrush to remove the paint. (If you let it sit long enough, it'll break the bond on some glues also)