One of the best paint strippers I've found is Castrol Super Clean. Purple stuff, biodegradable. Soak for 8-10 hours, and take it out and paint comes off in one huge slough. It will dry the heck out of your hands, though, so wear gloves. Safe on metal and plastic, and even the few resins I've tried, though it will soften the resin for about 12 hours after you take it out, but seemed to recure just fine.