[header] How to bleach your teeth [title] Bleach your teeth with baking soda. [step] If this stuff can be found in toothpaste, it's got to work. Turns out there are free radicals in baking soda that can penetrate through your enamel, turning stains clear. 
Just dip your toothbrush in the stuff and scrub away for a couple of minutes, just like you're brushing your teeth. [substeps] There has been some uproar about just how safe this is, for the record.