My next door neighbor's house is separated from mine by only our adjacent driveways, so their 3 cats that they are not capable of keeping inside (more on that later) consider our driveway and yard to be in their territory.

Our carport is gravel, as is the driveway, and the cats inexplicably use it as a litterbox, depositing huge piles that REEK next to our cars. We have to be careful where we step, and I now keep a pooper scooper at the opening of the carport for managing this. I love my neighbors - they are wonderful, wonderful people, but I am going crazy. The sprays that supposedly repel cats have no effect. I've tried sprinkling cayenne pepper, garlic powder and onion powder around, to no effect. I need to access the carport myself so I cant run any kind of fencing, of course.

The cats are EXTREMELY wily and when I house-sit for them, when it is my mission to keep the cats indoors, they manage to blast past me somehow, no matter how prepared I am. They are very good at this! The family has a toddler also that opens the door to their fenced back yard and can't be expected to keep the cats from escaping then.

So, I don't really blame them, but I just can't take the poop in my carport. The gravel is of varying sizes but I can't imagine any other substance that would be less appealing to them than gravel - I'd think that would deter them.

Don't get me started on hunting at my bird feeders......