Car collection in pole barn. Cement floors.
I put down 24 snap traps.
alot of glue traps.

Would peppermint oil also keep mice away from cars ??

For now, all cars will be stored with their hoods open !!

Setting a couple snap traps under each hood on the air cleaner/ battery and attach them with hercules putty so they stay put when a catch is made and much easier to see and find after a catch is made.

Placing a trap or two in the trunks or in the rear of each vehicle can keep a guy busy if you have any kind of normal mouse activity around your place.

The vehicles are the attraction and will have all the nesting material and harborage that they need and want. Those mice that avoid or miss the floor traps will surely find the traps within the vehicle very inviting.

Been doing this a long time. If you don't have a couple cats around it might be a good idea to get a few. They really help the cause.

Traps by the tires,,, that is were they climb up

Keep Bell laboratory's bait in stations along all walls. Must use quality poison and rodents will be far and few.

Once a rodent eats a lethal dose of rodenticide and becomes sick where do you think they go to die? Harborage areas typically. They go to the nearest opportunity of cover/shelter. Not good to have dead rodents in your vehicles.

Most likely that is where some will end up if the building has several vehicles stored in there. Trapping is the best choice to eliminate this problem. Stay on it and you can make it work. If not, there is a price to pay with chewed wiring, hoses, fabric, insulation and other chewable lines etc..

Bob has hit on an important factor in trapping around vehicles. Traps are best , rodenticides when you have no other options.

Worked at a car dealership years ago. Had this one car come in with a really , really bad dead rodent smell. It was RAW. A dozen tree air fresheners could not mask the smell. You literally had to drive with the windows down or gag.

Tracked it down to the passenger rocker panel. For those that don't know , the rocker panel is welded on , not attached with fasteners.

With the customer's blessing we cut open the rocker panel on a 4 month old car. Inside was the remains of about 9 baby mice turned into goo. Cleaned it out and dumped that trash can right into the dumpster. You could even smell it when walking past the dumpster until the garbage truck emptied it days later.

Made an appointment for the car's owner with the body shop to weld the rocker panel closed where we had opened it and repaint.

Sad to do this to a 4 month old car. I doubt insurance covered it

best I've found to work under my own cars is Tomcat repellent around the tires