You've seen those ageless Beauties—smooth, glowing skin and not a wrinkle in sight! Want to know the most common thread that runs through their skin care regimen? It’s Vaseline—otherwise known as petroleum jelly or petrolatum. The popular multipurpose balm is considered by many as their number one skin saver (Marilyn Monroe used to coat it on her skin in layers!), but what exactly is the stuff and what does it do to our skin?