The latest game-changing hair hack is dubbed "bathrobe curls," and you'll see why. This new technique involves using the sash of a bathrobe to make heat-free curls overnight. To do so, start by placing a belt from a robe on the top of your head, letting it fall to each side. You then divide your hair into two sections and wrap it around the robe belt. Once you finish wrapping your hair, sleep on the curls-to-be.