Probably one of the most common polish problems, this is also a tricky one. Nail polish remover can interact with some dyes and fabrics (it'll actually melt acetate), so perform a spot test before you use it. If you use remover on your fabric, then make sure to launder it directly afterward. And when remover isn't an option, you can always try hair spray. Dry-cleaning solvent can also usually remove polish, so if you can't get it out at home, then don't be afraid to run it down to your cleaners.