There are a few ways to help keep your cat's teeth clean without brushing them. Providing your cat with dental chews and toys can help to reduce plaque and tartar buildup, as well as providing them with mental stimulation. You can also give them crunchy food, such as kibble, which can help to scrub away plaque and tartar. Additionally, regular visits to the veterinarian for professional cleanings can help keep your cat's teeth healthy.