Housing collections

I have had a TERRIBLE problem with mice out in the garage. I've learned that you NEVER put a PC out there without blank card brackets in ALL open card slots and drives installed in ALL open media holes. I've recently thrown away an otherwise good Dell Optiplex Pentium III system because the mice set up housekeeping in it. There was a big obvious nest in it and signs that 'the little ones' were (im)properly raised as computer component enthusiasts. I still have a lot of systems out there but they're all carefully sealed. But I live surrounded by hundreds of acres of cornfields, and the mice converge on my garage every year when it gets cold. They've also chewed up ALL the power tool user manuals that I made the mistake of leaving in the workbench drawer. Sometimes if I'm out there and being quiet enough, the whole city of mice around me comes alive.