Turns your uneven, mangled eyeliner into a cat-eye worthy of the Triwizard Cup.
Removes your chipped nail polish in a flash, so you don't have to furiously scrub at it like Argus Filch with a dishrag.
Cleans your filthy makeup brushes when you're too busy with Transfiguration homework to do it yourself.
Locates a bobby pin when you need one faster than HP himself can catch the Golden Snitch.