You can buy these granules at a landscape place called Scat. It works well when placed in the soil. As to climbing on cars, you can place pieces of duct tape upside down and when the cat steps on it, it sticks to his feet which is the worst feeling for a cat. Cats also hate slippery cars that are well waxed. These are humane ways to deter a cat. I have heard about those high frequency noise generators but I do not know how well they work. Whats interesting is, if you give a cat plenty of attention, it generally stays within 1/2 acre. I've been a cat owner for 30 years and one thing my wife and I have discovered, if you give plenty of attention to a cat and make your property attractive such as leaving a patch of tall grass or planting catnip, you can keep them somewhat close, although we have seen our cats roam out of our yard. We have talked to the neighbors and none of them have mentioned feces in their much or any such thing. Our two cats are wildlife chasers and we have not been able to break them of this, They will kill skunks, rabbits, any rodent, birds and once even a baby coyote. They will not touch the ducks or geese since they have been around them since they were kitten. Our cats hate the sound of roosters and will run in terror. The problem is, once a cat has established its territory, its very tough to make them leave. This annoying cat you are talking about has probably sprayed on your car tires multiple times without you even knowing it. Then you drive somewhere else and another cat smells it and sprays on it again. Cats also hate citrus. As mentioned above, any dog is a good deterrent too, but that puts you into pet ownership.
