Nail polish is a solvent-based coating containing pigments and/or dyes used to create decorative effects on fingernails or toenails. It debuted in 1900 as a glossy nail varnish (applied with a camel-hair brush) that wore off in a day, but today’s polish is the icing on the manicure — and pedicure — cake. More than 90% of nail technicians retail polish in their salons and spas, and more than half of nail technicians offer three or more polish lines in their services.