Squeeze one whole lemon and add a tablespoon of baking soda until you make a thick creamy paste. Leave on for up to 20 min, then rinse with cold water. Make sure you make a thick creamy paste. If it's too watery, add more baking soda.
Another Pinner Wrote: DIY Teeth Whitening Remedy Dr. Oz Teeth Whitening Home Remedy: cup of baking soda + lemon juice from half of a lemon. Apply with cotton ball or q-tip. Leave on for no longer than 1 minute, then brush teeth to remove.