Japan
What: Nightingale droppings and rice water

The history: A few years ago, Uguisu no Fun — powdered nightingale excrement mixed with soap — was all the rage. Even the beautiful Beckhams were rumored to be fans. However, King suggests opting for more tried-and-true exfoliants, like centuries-old rice water, to wash your face.

The lowdown: Nightingale droppings contain an enzyme that exfoliates the skin. It includes guanine and uric acid, which may have a brightening effect on your skin. However, uric acid is found in most waste, argues King. "You could rub your urine on the skin and could probably have the same effect, but does anybody really want to do that?"

Rice, on the hand, with all its Asian history and heritage, contains phytic acid, which also brightens the skin. Additionally, the grain also makes for an excellent exfoliant when not refined too much.