how do you whiten your teeth with baking soda?

I've heard people saying baking soda helps restore natural whiteness, but what do you do? just brush your teeth with it?
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I pour hydrogen peroxide on my tooth brush and then dip it lightly in the baking soda. The peroxide whitens and the baking soda breaks up stains. Other times when I just want to use baking soda I put toothpaste on my brush first, then dip the toothbrush in the soda. By the way, hydrogen peroxide is really cheap and is usually used as an antiseptic. You can buy it at any store over toward pharmacy area.
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