Years ago when I was a kid grandma used a 50-50 mix of salt and baking soda. Said it kept juice, coffee, and tea from staining the teeth. I added the Terramin clay to the mix just to see what would happen.
My gums were getting better even before I started pulling with the addition of the clay to the mix.
I mix 1 heaping tablespoon each of baking soda and "Real Salt" in addition to a teaspoonful of the Terramin into a small Tupperware and use until gone. Then I mix another batch. http://www.terramin.com
I have heard of one other doing the same mix (may not be same ratio) getting their toothbrush wet with hydrogen peroxide... not sure how this would work with the peroxide and I have not tried it as I have not found a local source for food grade peroxide. Might go to a livestock feed store and see if I can find some.