Question
any suggestions how to keep the neighbors cat from pooping on my lawn?

Answer
Hi drew;
I tried every cat repellant that was safe for cats, that was on the market, and none of them worked.
Then I read that lemon peels repel them, so I bought a couple dozen lemons, sqweezed them and froze the juice, and chopped the peels very finly. I sprayed my flower beds with Amway's LOC, and then rinsed it to get as much of the cat smell off as I could, then scattered the chopped lemon peels all around in the flower beds.
It stopped the cats completely.
Every time I use a lemon, I chop the peels and toss them. I keep a grid in my mind, so I am scattering to the next spot each time. That keeps all the areas with newer peels.
If you are wanting to treat your entire lawn, I would get some lemon oil. Go to a health food store and get the 100% lemon oil.
Use something that will suspend the lemon oil in water, like LOC, if you know an Amway dealer and can get some of that, it is good.
Agricultural soap should work. You should be able to get that at a nursery or possibly at a feed store.
To one gallon of water, use 1 teaspoon LOC ( or even a dishwashing liquid. Joy is lemon scented.) and about 1 TABLESPOON lemon oil.
Spray that all over the lawn, and you could chop the peels of a dozen large lemons ( maybe more) and scatter then along the perimeter, about 2 feet wide.
That should repel the cats from even coming in the yard.
Grapefruit peels repel dogs. Orange peels will get rid of fire ants.
Lemon peels get rid of some types of ants. You could actually mix all those peels. Orange oil is the main ingredient in the effective fire ant treatments.
Charlotte