You use your brushes daily, but how often do you give them an important cleaning which they actually need? And when's the last time you got a new set of efficient, fluffy brushes? Dirty brushes are riddled with breakout-causing bacteria — and that's just one of the gross things that happens when you don't wash your tools. Then there are old, scratchy, dirty brushes, which can negatively affect your skin and your makeup application. "Try washing them in a nourishing soap. If that doesn't work, buy some new ones," says makeup artist Katie Jane Hughes. After all, great application brushes are worth the splurge.