Bad Manners and Brimstone

At our previous house we had a problem of some people letting their dogs poop on our lawn. I would find it when I mowed. I knew is was not neighbors on our street, but never saw the people with the dogs. I purchased a can of black pepper and spread it over the the first three feet of the lawn. Any dog sniffing to find a spot to do their business would get a nose full of pepper. This solved the problem.