DIY Teeth Whitening- 2 parts baking soda, 1 part hydrogen peroxide. Mix the 2 together until you get a toothpaste consistency. Fill the tray of a mouthguard, pop it in your mouth and leave for about 10-15 minutes. It might take a week or so to achieve the whiteness you’re looking for.
"Put a tiny bit of toothpaste into a small cup, mix in one teaspoon baking soda plus one teaspoon of hydrogen peroxide, and half a teaspoon water. Thoroughly mix then brush your teeth for two minutes. Remember to do it once a week until you have reached the results you want.