Gloopy (and therefore expired) nail polish isn't going to hurt you, but the bacteria growing on your face makeup can cause red bumps, pink eye and other health problems. Eva Gizowska of iVillage wrote about the shelf life of costmetics, how to tell it is old, and tips for making your makeup last. (I didn't know that lipstick only lasts two years and that perfume can be preserved by keeping it in the fridge.) The best way to make sure you're not using rank product is to write the date you opened it on the container.
Get cleaning, ladies!
Image source: The Looking Glass