I've been using "The World's Best Cat Litter" for many years and loved it. It is absorbent, clumps well, is flushable and almost dustless, and doesn't have any chemical odor.
This morning, disaster! I opened a new bag of "The World's Best Cat Litter" and a moth flew out! There were more in the bag, plus some tiny critters (whatever moths were before they got wings?). I took the bag back to my pet store, and they replaced it. But I'm reluctant to use the replacement; a friend told me that this happened because the litter is corn-based. Maybe I'll switch back to clay-based litter.