You can make out the two baby mice on my in-cabin filter of my previous truck. The truck would sit idle for a week or two at a time. Be sure to set your vehicles HVAC controls to Recirculate to close the fresh air intake while parked. Two years later, I found a leaf and stick nest about a foot and a half diameter under the hood. Squirrel, I suppose. I cleaned it up very well and inspected for chewing damage but I didn't see any. I went about my business and forgot about it. Six months later, I traded that truck in, driving it to their dealership with no issues. A week later, my sales person told me the truck died on a test drive. They replaced chewed ignition wires under the hood. Recently, a local mechanic suggested I try Bounce Dryer Sheets. I guess if duct tape or WD-40 doesn't fix it, throw some dryer sheets at it.