One of the downsides to having the sickness of collecting old cars is the battle with mice.  They leave a disgusting mess and can do serious and hidden damage. So, I fight them as best I can. I've tried poisons and they do work but worry that my dogs might get into that as the mice will actually carry the poison (like a coveted stash) back to their permanent home. In once instance I had poison inside my closed-up 911 project but, within a few days, found the poison stacked up in a nice heap at the garage door.

So anyway poison is out and the main battle plan is to deny access wherever possible with simple security. I keep the doors, sunroof and windows closed. I try to find any openings where they can get in and devise a way to deny access.

Here's a favorite way in for smaller mice. For now I just a put a bolt and fender washer over this drain hole in the spare tire well.

I don't open the air filter housing every day but it is not unusual to find the beginning of a nest there. Hopefully this at least till I can come up with something more elegant.