Using Baking Soda Whitens Teeth by Mare Bear Using Baking Soda Whitens TeethMake a paste with water and baking soda. Apply to toothbrush and brush away. Do this 2 to 3 times a week to achieve your desire look. Unless you don't like the taste of just baking soda alone, then you can mix the product with your regular toothpaste on the day you are going to whiten. Drug store whitening products can be pricey and contains too many chemicals that can ruin teeth enamels. Whereas baking soda is a natural product that breaks down any stains and tar, and its definitely a cheaper remedy for a healthy smile.