How do I keep the neighbors cats from using my garden a litter-box?

ok I know how mean this sounds, but I have a similar problem with the cats marking my car. I bought a $25 bb gun from walmart and I only pump it once. It only took 2 hits in the butt to keep those cats away. Again I know its mean but its the best solution that I came up with. And, yes, I do have pets.....2 dogs and a cat!

My parents had this problem long ago. One of them asked what to do at a garden center, they said mix water and a jalepeno in a blender and pour around flowers/plants. They said it won't hurt the flowers and the jalepeno smell will keep the cats away since their noses are very sensitive.

moth balls in a old sock will keep them away.