Keeping Stray Cats Out of Your Yard?
For around your patio and door try using T-lights made out of Citronella bought at Cdn. Tire in a bag. Just put them around the area as they are and not lit. Cats dont like the scent. It worked for me.
Keeping Neighbor's Cats Out of House and Garden?
Buy a bag of citronella tea lights at Canadian tire and put them all around where you dont want the cats and they will keep away. They dont like the smell. It works really well and lasts for quite a while. It was great for me.