What should i do to whiten my teeth and why are they yellow if it isn't stains?

Natural/bleaching: First, there is individual natural variation in tooth color. Some people have naturally white teeth. Some are yellow. Some are grey. People have blonde, brunette, or red hair. Eye color is also individual. Second, bleaching with the many products on the market works, however one should note in the packing the instructions these can get your best natural color.