Sodium bicarbonate can raise surface spots but does not bleach tooth color; use sparingly
https://sergiojedw518.almoheet-travel.com/how-to-maintain-your-results-for-approximately-a-year
Baking soda can lift surface area discolorations however does not bleach tooth color; use moderately, and couple with fluoride toothpaste to protect enamel and reinforce teeth.