1. Has the vet been consulted about this particular problem?

2. Has he tried Cat Attract litter?

3. If she was a stray, could she find the litter box too small?

4. How often is the box cleaned?

5. There is a pet psychic here that has helped a lot of people. Also, a pet behaviourist may help, though I don't know how much they are.

6. Is she spayed?

Hope something gets figured out!