If you've ever used Vaseline, you're probably familiar with petrolatum (aka, petroleum jelly). Derived from petroleum (the same kind used for gasoline and other products such as deodorant), petroleum jelly is a staple in many people's medicine cabinets—and for good reason. It's great for smoothing and protecting rough skin. "Petrolatum is an occlusive ingredient that prevents water loss and an emollient that hydrates the rough dead cells on the skin's surface," says Zeichner. If you have dry skin, be sure to look for petrolatum on a product's ingredients list. Folks with normal to oily skin may want to skip petrolatum, though, as it may exacerbate greasy skin.