This is something my mom always told me when I first started wearing make up at 13 years old: Don't use anyone else's make up. You could get an infection! And its true. But you can also get infections from you're own make up or just applying make-up with dirty fingers.
Washing your hands is a simple way to prevent infections and getting foreign objects in your eyes (like dirt, lint, etc.). We've been taught this for as long as we can remember! Clean hands aren't just for applying make up! On top of clean hands, try not to put your brushes, wands, or other make up application tools on counter tops. It exposes them to germs that can be damaging to eyes or skin.
Above all, don't share your make up or application tools with other people without cleaning them first. Even at make-up counters when testing make-up. Here's a video on Cosmetics Counter Etiquette Tips by Petrilude.
Did you know it was a potential risk to use somebody else's make up? What other myths have you heard and want to clear up?