So when you say you've tried everything have you tried Swheat Scoop, Feline, Fresh, Feline Pine, Yesterday's News, etc? These are litters that are wheat based, pine based (yes, trees), and recycled newspapers. There are also a few others that I haven't mentioned. Lots of different options available beside the ol' crappy clay and they are much better for the environment than is clay.
I'm a little confused by your comment about using the Arm and Hammer because it's better for their digestive tracts though........
Assumptions do nothing but make an ass out of u and me.
We can stick our heads in the sand for only so long before it starts choking us. Face it folks. The pet population is bad ALL OVER THE WORLD!