Once he has been successfully and routinely using the new litter you can remove the other litter boxes.
No Abrupt Changes When it Comes to Cat Litter
The worst thing you can do when it comes to changing litter brands or types is to merely dump out the contents of his current box and fill it with an unfamiliar litter. Every time your cat goes to the litter box, as a creature of habit, he is expecting to come across the same texture against his paw pads and the same scent (or non-scent). Even if you’re absolutely sure he’ll like the new litter better, use one of the above two methods rather than using the element of surprise.
Need More Information?
If you have a question about your cat’s behavior, you can find information in the articles on our website as well as in Pam’s books. If you have a question regarding your cat’s health, please contact your veterinarian. This article is not intended as a replacement for your cat’s veterinary care.