Mice & rodent repellant

Mice problems? Every fall we have mice trying to get into the house and get trapped in walls and smell. We have a local site: www.pinecam.com, that started up when the forest fires were starting up everywhere and shifting with winds, and us locals were frustrated with the news source down in Denver. So now there's cameras posted all over and people reporting in for everything from bad weather, traffic, lost animals, recipes, restaurant reviews, etc. It was there I found this recipe.

I've not made and tried this rodent recipe yet. Monte's mom just told us about their mice problem in Wisconsin and I gave her the recipe. I just know from all the chat letters, that people said it really worked. We do need to use it, though things have changed. Since the garage got that spray-on, expanding foam insulation, for a bit we were smelling mice where we've never smelled them before. I think they're 'lost' since their typical paths have been eliminated.

1 gallon water
1 onion, chopped fine
2 jalepeno peppers, chopped fine (I often where gloves when handling jalepenos. If you forget and wipe your eyes...:( sob)
2 TB cayenne pepper
Boil 20 minutes. Strain. Pour or spray around holes and house edges.
Some people told stories of spreading the strained solid stuff in critter holes too.
Someone said adding oil, it could be 'painted' on.
Most said they only had to do a couple applications in spring and another in fall and it's worked!