Baking soda and hydrogen peroxide for removing coffee stain

With the use of Baking soda and hydrogen peroxide you can whiten yellow or coffee stain

Hydrogen peroxide, which is an oxidant, causes the enamel to release the coffee particles that discolor the teeth. In contrast, adding baking soda accelerates the process.

To prepare the combination, add a few drops of hydrogen peroxide in a clean empty bottle. Make a paste by mixing in baking soda and water.

Brush your teeth with your normal paste after letting the paste sit on your teeth for 15-20 minutes. If you stick with it for a few weeks, you'll start to notice benefits. Read here if you want to know more remedies
How to Remove Coffee Stains from Teeth