4. Baking soda
One 2008 study found toothpastes that contain baking soda — long considered a tooth-whitening home remedy — do a better job of removing plaque than toothpastes without the ingredient.
To try it, your best bet is brushing with a commercial paste that contains the mild abrasive.
Or, once in a while, you can just brush your teeth with baking soda straight from the box.