Fix: 1 tbsp of hydrogen peroxide with 2 tbsp baking soda. Use a cotton swab to apply the mixture to the nails and underneath. Leave it on for 2-3 mins, rinse with warm water. Baking soda will exfoliate, while hydrogen peroxide will whiten. * Mix 1 tbsp coconut oil with 2 tbsp baking soda, few drops of lemon juice and apply to nails. Brighten, exfoliate, and give moisture.