Not necessarily true. I use acetone to strip plastic minis all the time with no loss of detail. You dont need to soak them, just use a toothbrush dipped in acetone to scrub the paint off. Obviously you will destroy your mini if you soak them.
I wouldn\'t recommend it! Although acetone don\'t melt your plastic right away it doesn\'t take much to damage the mini. It works for resin though, it seems, and metal of course.