I had this problem 2 years ago, but on an Accord (still saving for an E). Solutions that seem to have worked:
1) As mentioned by others, keep the environmental controls on "recirculate", as the mice tend to get into the interior via that route.
2)I also put oil of peppermint (real oil of peppermint, not extract) on cotton balls around the interior and the trunk, and also dripped some on the carpet and into the air vents.
3) Finally, I put pest repellant packets (dried coyote urine, I think) in the engine compartment (attached them high in the compartment with twist ties, and out of the way of moving parts). The reason for putting them high in the compartment is that I was very kindly warned on here that, if they get wet, they smell awful; I'm assuming they stayed dry, because there was no smell in the car.
I don't know if they stayed out of the engine area (although it's been in for at least two mechanic visits, and he didn't mention anything), but they didn't return to the interior. Of course, the car smelled like Santa's Workshop all winter.