Mouse prevention

Hello everyone,
Well,it's that time of year again (at least for us unlucky northerners): time to store our favorite rides for another long winter.
I just scored some nice storage in a brick garage on an estate not far from my home. I'll move 2 into it, & have my 2 car garage to work one another.
The estate is out in the country, so I'm concerned about keeping mice out of the cars. I've heard all the stories: mothballs, drier sheets, even Irish Spring soap (my friend tried the soap in his wife's 'Vette last winter: the mice ate the soap, & crapped it back out in the car!).

I'd love to hear what everyone does to prevent the little rodents.

Thanks

Dave