Many people automatically assume their polish has just expired. The term “expire,” in regards to cosmetics, the FDA says that there are no actual requirements in the U.S. The only concern is bacterial growth.
European products, however, have something called “Period of Time After Opening,” which is a symbol found on cosmetics. These kind of symbols can be found on brands like China Glaze and OPI.
Even though the PAO is required for all European Union products, it is not a factor when it comes to nail lacquer. According to OPI, nail polish does not go “bad” with bacteria after opening (or ever), because the solvents are chemically hostile to microbes.
So, rather than tossing out your old, seemingly ruined collection of polishes, the experts suggest using nail polish thinner. The common myth is just to add some polish remover, but this is wrong. Remover is too harsh to add directly, so opt for thinner that is sold specifically for this purpose.
If you don’t believe us, we’d gladly take your “old” nail polish off your hands…