Imported clumping litter is excellent and the price has become silly. So people improvise, with mixed results.
What is in use:
- Bentonite clumping litter, imported or repacked
- Silica crystals
- Sand, plain, from wherever sand comes from
- Sawdust or wood pellets
- Shredded paper
- Ash, which people still recommend and which is bad for paws and lungs
The trade-offs are cost, smell control, tracking through the house, and whether the cat will actually use it -- a cat that dislikes the litter will find your bathmat instead.
Tell us: what you use, roughly what it costs you per month per cat, and whether your cat accepted the switch or protested. Switching gradually by mixing the new into the old seems to be the trick.