Have you ever returned to your favorite nail polish only to discover that it was hard to apply because it was sticky and dry? It's very tragic, isn't it?
Acetone is here to help
Hot water works wonders
The best treatment is prevention
The only thing you need to cure thick, dried nail paint is a bowl of hot water.
Simply one drop of pure acetone will do to smooth out your polish. More than 1 drop will cause the nail paint to degrade and shorten its shelf life.
Make sure to tighten the nail polish bottle's lid after each use. Never open the lid for any longer than is required.