You don’t need to buy premium stuff from healthfood stores, but it has to be genuine charcoal.
Don’t use regular old charcoal briquettes. I don’t trust
the additives. - Get the kind from the health food store,
or Walmart pharmacy in capsule form.
I’ve tried it brushing my teeth. It stains the gums BLACK.
Not a good look. So, I use Arm & Hammer baking soda &
hydrogen peroxide or Uncle Harry’s tooth powder with
white pearl powder added to it. - I avoid fluoride.