Way back before I heard of paleo I started experimenting with brushing my teeth with baking soda. I really enjoy the way it makes my teeth feel squeaky clean. I'm not crazy about the weird salty taste, though, nor the weird flavor it leaves in the mouth. In fact I usually brush my teeth with toothpaste after using baking soda cause I like that minty fresh breath.
I also use vinegar on my hair with more success (this also started before I'd heard of paleo), as a cure for dandruff and it works like a charm. My Swedish friend who was staying at our flat thought it was pretty bizarre. "Why does the bathroom smell like vinegar?" "You shower with it!?" Yeah, well at least I don't eat rotten fish.
I try to avoid shampooing often which is a lot easier when my hair is super short, but haven't been able to give it up completely. I'm just not able to tough out the two month or so adjustment phase. What a slacker.