The Truth About All-Natural Teeth Whiteners
Why: Physically scrubbing your teeth may actually have some effect on surface stains, says Messina. However, it's essential that the substance not be so gritty that it wears away enamel. Baking soda mixed with water is just abrasive enough, and Messina says that baking soda toothpastes that have the American Dental Association seal have been found safe to use with a soft toothbrush. (You can also try "whitening toothpastes" that have enzymes to help dissolve surface stains.)
What not to try: Brushing with sea salt, rinsing with activated charcoal (Messina says that there's zero clinical research behind it). They sound so wacky they just might work, but Messina says that these DIY don'ts could cause serious, permanent damage to your enamel.