how could it melt the body???????? is it a regular plastic model kit?? who made it???
anyway if it were tamiya acrylic you just use 91% isopropyl alcohol from your local drug store.. very cheap. fill a bowl with half a bottle and just dip the body in it. tamiya acrylic is the EASIEST acrylic to remove. and alcohol is 100% safe for plastic.
if that doesnt work try this.. polly-s easy lift-off
if that doesnt take it off you can try those brake fluid or something that other people have mentioned.