It's almost April, so it's time for a little spring cleaning... of your makeup bag, that is. Since expired cosmetics can cause skin irritation and eye infections, it's important to replace them before they go south.

Unlike food, though, cosmetics aren't required to have an expiration date on their packaging. Instead, you'll have to keep track of when you opened it. Most products have a symbol similar to this one, in which the number signifies the number of months you have until the item is no longer usable. If you have a hard time keeping track of when you've bought things, just use a Sharpie to write down the purchase date.

If you know how to take care of your cosmetics [1], your makeup should serve you well. But use common sense: If your gloss is gloopy, your nail polish is separating, or your lipstick has a funny smell, it's time to bid it adieu. To see guidelines for when to replace your makeup, .