Fresh brushes and sponges ensure that your products glide on flawlessly, but they also keep harmful buildup off of your skin, as makeup pro or dermatologist will tell you. “It is important to clean makeup brushes to get rid of dirt, oils, and most importantly bacteria," says Cristina Monaco , certified physician assistant at Schweiger Dermatology Group. "I find many patients complain of increased acne breakouts if they do not clean their makeup brushes consistently."