Nail polish stains on wallpaper can result from an accident or the artwork of a creative child. In either case, it is best to attend to the stain quickly because nail polish dries fast. Dab at the stain carefully to remove as much of it as possible without spreading the stain then try one of the following stain-removing techniques to remove the rest.
Rub off with acetone or acetone-based nail polish remover. Apply a small amount of acetone to a cotton cloth and dab it against the nail polish. Repeat until the stain disappears. Acetone is available at home improvement retail stores.
Use melamine foam. This effective cleaner, composed of formaldehyde-melamine-sodium bisulfite copolymer, was originally used as insulation. Commercial products made with this foam include eraser-type cleaners. Moisten the foam with a small amount of water and rub it against the stain until it disappears.
Apply a small amount of rubbing alcohol on a cotton cloth and rub against the nail polish stain. Repeat until the stain disappears.
Chip off the polish. In "Haley's Cleaning Hints," the author advises holding an ice cube against dried nail polish to make it more brittle. Use a tool with a sharp blade to chip off the paint, such as a penknife or a razor blade. Dab the area with acetone, wiping it off with a paper towel as you work.