See this at: nytimes.com| Added on 10/27/09

CONVENTIONAL clay-based litters may be absorbent, but they’re not environmentally friendly. (Most are not biodegradable and some have ingredients obtained through strip mining.) Clumping brands also may cause digestive problems if ingested, although... See more

CONVENTIONAL clay-based litters may be absorbent, but they’re not environmentally friendly. (Most are not biodegradable and some have ingredients obtained through strip mining.) Clumping brands also may cause digestive problems if ingested, although there is some debate about this. In recent years, a variety of natural litters have come on the market, made from wheat, corn and various kinds of trees. The five brands I picked to compare, which show up frequently on pet supply Web sites and blogs, are made from a range of materials. While the testers’ cats used the litter in the normal manner, I assaulted the products with ersatz waste — primarily ammonia, a cup at a time. Where applicable, I dug up clumps with a scoop. Two of the litters tested do not clump; you scoop only the solids, for which I substituted stinky things like sardines and garlic paste. Swheat Scoop is, yes, wheat-based. It has a mild whole-wheat flour aroma, and its texture is grainy, like clay litter. Mister, a... See less