The secret to this inexpensive home whitening method is malic acid, which acts as an astringent to remove surface discoloration. Combined with baking soda, strawberries become a natural tooth-cleanser, buffing away stains from coffee, red wine, and dark sodas. While it’s no replacement for a bleaching treatment at your dentist’s office, “this is a fast, cheap way to brighten your smile,” says Adina Carrel, DMD, a dentist in private practice at Manhattan Dental Arts in New York. “Be careful not to use this too often, though, as the acid could damage the enamel on your teeth.”

You need:
1 ripe strawberry
1/2 teaspoon baking soda

Directions: Crush the strawberry to a pulp, then mix with the baking soda until blended. Use a soft toothbrush to spread the mixture onto your teeth. Leave on for 5 minutes, then brush thoroughly with toothpaste to remove the berry–baking soda mix. Rinse. (A little floss will help get rid of any strawberry seeds.) Carrel says you can apply once a week.

Source