Have they always used saw dust? Or has it changed? I know my cat is very particular about litter. If I buy something different he wont use it. Other than that, I don't know how else to help. I can imagine having cats in that situation...guess I'm de...

If you have more than one cat, I would try adding another box. Have there been any changes in the litter...texture, smell, ect? Is the box near its food? I would also make sure the spot where he goes is throuroughly cleaned. I have had a good experie...