I use them too. Bounce brandI've used fabric softener sheets with good results.
Steel wool works great for plugging holes, I had mice chew spray foam up and get in the house anywaysI have used these in my camper and I thought it was working until I found the mice had collected a few of the cotton balls for a nest. The smell was more of a deterrent to me than the mice. Use traps to stay ahead and try and plug holes with spray foam.
I love those traps, we always put out 3 or 4 around the shop at work each winter just so we can check them every day. It's kinda like running a mini, indoor trapline. LOL We use a pile of peanut butter on the end of the "plank" and sunflower seeds leading up to the pile.I also built a bucket of death and will be putting that out.