[clarodcobra]

You may want to consider using plastic cups to cover the ends of exhaust pipes. A few years back during the winter, I started my MGB and corn blew out the ends of the pipes as if I had used a shotgun. Apparently, rodents liked the exhaust system to store their food (corn). I kept corn in plastic container to feed deer but learned a lesson and now use a metal garbage can. In addition to above mentioned dryer sheets and mouse traps, I recommend the cups. One can also use steel wool to plug smaller exhaust pipes, etc. Mice cannot chew through this material. However, post a note to remove it come time to start the car!