You should stop drinking so much coke because you're going to get cavities and need a lot of dentist work down the road If you don't. Or atleast use a straw to avoid acid erosion. Baking soda whitens.

Just dip your toothbrush in water and then into the baking soda and brush like you normally would just don't brush too often with baking soda as it is an abrasive and can damage enamel.

http://www.wikihow.com/Whiten-Teeth-With-Baking-Soda

View the original article here