"I also put moth balls under the hood in a perforated baggy to keep the mice out".. I used to use moth balls, until a fellow told me to try "Mint" in liquid form.
He said to use a use a a small tin container, place cotton in it and pour the mint over and close it up, then punch a few small holes on the top. I tried it and to my
surprise it worked very well, just keep the cotton moist with more mint as needed. It sure smells a lot better than moth balls and works as good or better.
I found a chew tobacco tin woks well, you can place a magnet on the the tin and stick anywhere you want it, I also placed a few in my shop cabinets and no longer
have mice. I can't begin to say what it is the mice don't like, but whatever it is I like it..