The clay is not that special, it is called bentonite. You can order it by the pallet load, and it is a whole lot cheaper than cat litter. I'm surprised that t

The clay is not that special, it is called bentonite. You can order it by the pallet load, and it is a whole lot cheaper than cat litter. I'm surprised that the spec did not call for bentonite directly, and that no one in these comments has mentioned it either. http://en.wikipedia.org/wiki/Bentonite http://en.wikipedia.org/wiki/Bentonite