How about putting up some high-frequency emitting mouse repellers? They´re little boxes that connect to a wall socket and put out frequencies that humans cant hear but drives the mice and rats away.
My dad works for a fuel distributor, their base is down by the docks and I´ve never noticed mice there. They have around 10 trucks in at any given time, alot of houses and sheds and big piles of hoses, oil traps and other places were mice could find shelter.
I´ve worked on my truck in their shop and never saw them running around. I got to keep my parts truck there for a year and it was mouse free when I stripped it down. They have these repellers and they don´t even bother with poison anymore.
