Buy powdered clay, I have a couple of sources. When I first read about it, I split a huge bag with a room mate which lasted me for years and I gave some away.
Now I get it by the pound (dry powdered clay with no additives, not for potters), best for medicinal use is french green clay or bentonite (green is a type of bentonite). My cost is about $7-8 a pound last I looked (Starwest Botanicals, w/s price) but you can look around.
I should visit the Natural Healing thread and discuss it there. I am never without a bowl of clay, it has many uses.
If/When you visit the other thread please ping me.