If you don't want to use any commercial bleaching product, you may get minimal results brushing with baking soda and water in a paste. It forms a slight abrasive which will help get any stains off your tooth's surface.
Rinsing with a water and hydrogen peroxide mixture can also be effective as it has a mild bleaching affect.
These will help but the difference will be minimal.
Hope this helps.
Best to you,
Gellia
An answer would be nice..