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.
If you swish with hydrogen peroxide everyday you will have the same results plus excellent gum tissue! Recommend swishing with peroxide for minutes morning and night. It kills bacteria that causes decay, gingivitis, periodontal disease. Worth a shot!