Liquid nail polish remover with Acetone does more than remove nail polish. It is useful for removing paint, both enamel and acrylic. I have used it on both plastic and metal with excellent results, however, you should be very careful with plastic. Acetone is strong and can melt it if left on for a long period of time.
I particularly like to use it to polish my rails after painting and weathering.
I pore a small amount of remover into the lid and using a cotton swab, skim the tops of the rail head, moving the swab back and forth like you would sandpaper. The paint will come right off. No scratches!