<<Disclaimer: Verify this information before applying it to your situation.>> Hi folks, Bobbi wrote: > He looked startled, and said it was a kind of clay used to line >landfills (he works for the Maryland St. Dept. of the Environment, and spent several years in Solid Waste Management). Bentonite is also used as a clarifier when making home-made wine. It is definitely a type of clay. It bonds to suspended particles and pulls them to the bottom of the carboy. Pat in Toronto