I want pearly whites, but im stuck with soda stains!?

Can someone give me a hand? Im looking for an inexpensive way to whiten my teeth. Im an ex-smoker, and soda freak, so i have dark ugly stains, and my teeth are a brown tint! Its embarassing, and I brush twice a day and floss. Any suggestions besides lying off on the soda (already did that....)?
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The Herbal Body Book (A Natural Approach To Healthier Hair, Skin, and Nail) by Stephanie Tourles says that....

"strawberries have a slightly bleaching effect and help to rid the teeth of tea, coffee, and cigarette stains. A strawberry is much safer to use than lemon juice, which is too acidic."

Her recipe for Strawberry Brightener
Mash 1 medium-sized ripe strawberry. Dip your brush into the liquid and brush normally.

From the Answerer:
I must warn you that the seeds get stuck in your toothbrush, so you may want to have a separate brush just for the strawberry treatment. You would want to do this after regular brushing with toothpaste, of course. You can use thawed out berries that have been frozen, but make sure they do not have sugar in them (and that they’re not still cold). This is a tasty way to treat your teeth!

***This book has great recipes for natural facial steams, scrubs, toners, moisturizers, cleansers, masks, shampoos, etc. I got mine from Amazon for less than $4!!!