I was looking at the article that said you could keep cats out of the garden with predator urine— but not where to get it.
This year I put some Ammonia (grocery or hardware store) on a paper towel and put it inside a sealable baggie. Then I poked holes in it and threw it around where mice would normally be a problem. I had no mice all winter.
Cheap and effective because the critters think it is a predator.
Roberta Docherty, Meaford