I've been working on a scratch-built magical battle platform for a Lich, for my 2e BattleSystem fantasy games. I decorated it with Halloween Skeletons, cut up, and glued to the platform base (thin plywood); I 'painted' the skeleton bones and skulls with Minwax urethane-stain to base coat them; next I painted the platform using metallic blue nail polish; I further applied purple and metallic gold paint to the skulls, with silver metallic, to indicate that it is enchanted with magical defenses. The nail polish, however, got blotched onto bits it should not have (on top of the Rib Cage, bottom left; on the three Skulls in the middle and rear; up the bases of the Skeletal Hands, in the rear; and other places not shown).
No worries, I have Nail Polish Remover/Acetone, and Q-tip swabs!
I carefully wet the cotton swab tips with Acetone, then I gently rubbed off the excess nail polish (dried for weeks, by this point!), and it came off easily (white areas of the three Skulls in the middle and rear; the bases of the two Skeletal Hands, just behind the front Rib Cages). However, the urethane-stain (baked @ 200F, weeks ago, to fully cure it) also came off, quite easily, revealing the white plastic skull which had been lovingly aged with that 'Just dug up', look.
Short reason for posting this topic: Acetone will remove paint, nail polish, and urethane-stain from plastic, metal, and resin figures. Acetone will also dissolve some plastics (ABS!) if applied for too long. Fortunately, Acetone also evaporates very quickly (Yes, Virginia, Acetone is quite flammable, so use it with good ventilation!).
If you need to spot clean a figure, base, whatever, Acetone is your friend. Cheers!