Although the dangers of your own makeup becoming seriously contaminated are slight if they are quality products manufactured with proper preservatives, the same does not hold true for shared products.

Never share cosmetics, not even with a family member or a best friend due to the risk of contamination. And that risk goes up dramatically with shared-use products such as makeup testers in stores and at makeup counters. At home, your makeup usually has the whole day to cope with contaminants before it is used again. But makeup testers in stores are used much more often. According to the FDA, the preservatives in the products cannot handle the challenge of constant use.

The same holds true for those free makeovers at makeup counters. The products used to create that impressive new you may have been used on dozens of other customers before you.

Recent tests done on shared makeup testers by several independent news shows, such as the Today show, found dangerous bacterial contamination, including staph. If you want to test makeup shades, insist on new, individual applicators. Better still, test the makeup on your hand or the inside of your forearm. Never try on makeup from a tester using a shared applicator wand or brush.