Mice can cause serious damage to your car. The sweet smell of engine coolant, combined with warm nooks and crannies as well as the possibility of food inside the car, will attract mice to your car almost like that is what you wanted. When in your car, they will chew through and damage wiring, plastic vents, and leave nasty smells and rubbish. Getting mice out and keeping them out does not need to be a major inconvenience, however. With a few commonly found items you can deter mice from ever stepping a paw inside your car.
Place two or three fabric softener dryer sheets under the seats of your car, as well as in the trunk and under the dashboard. The chemicals in dryer sheets are very offensive to mice, who will find a more hospitable home than your car. They will also leave your car smelling as though it just came out of the wash.
Place moth balls throughout your car. Although they do not smell as nice as dryer sheets, they work on the same principle and can be easy to store under your car's hood where mice often nest and attack rubber and electrical lines. It also helps to scatter some in the garage your car is parked in to prevent mice from nesting there.
Surround your vehicle when parked with a vertical wall of aluminum sheet metal. This only needs to be 2- to 3-feet high and can be braced in place using 2 x 4s. This solution is only convenient if leaving a car parked outdoors for an extended period of time. Mice cannot climb over the vertical aluminum, nor will they dig under it just to get to your vehicle.
