Amazon.com : Ultra Micro Crystals Cat Litter 5 pounds : Pet ... Dec 11, 2009 · Fill clean litter box with 2 inches of litter, scoop solid waste out daily then stir crystals, then monthly discard litter, clean litter box, refill. Compare with similar items This item Ultra Silica Gel Crystal Cat Litter- Soft-On-Paws, Superior Odor Control, Low Dust