Classic story of 914 adventure. I'd suggest trapping the mice before they get in the car. Adopt a cat.

https://www.hagerty.com/media/maintenance-a...tion-gone-awry/

Mine came included in the purchase price!
Driving it home from the sellers place, about 3 hrs, I open the vents for a little air flow and was barraged with seeds etc. My daughter who hates the thoughts of rodents, asked what it was and I quickly said nothing, closed the vents, pulled over and showed her how the targa top came off and fit in the trunk!

I see dead rodents!

I see them all of the time...

Both stories were LUCKY!

Normally the car smells like a corpse as the rodents tend to get caught in the blower motor...

They LEAK when they rot!

If I vomit when I'm pulling dead rodents from your HVAC system, the price goes UP!

Modern vehicles have cabin air filters, and the vermin make nests on the top of these.

They eat holes in the filter, and everything is fine until the blower starts sucking...

I advise customers to ALWAYS leave the HVAC in recirc. Both heat and AC work better and the door being closed tends to keep them OUT.

Many cars default to fresh during heater operation. Select recirc manually to avoid the stench!

When I bought my they had created a Hab a Trail inside the car under the dash down to the rack and pinion it took months for the smell to go away and new upholstery.

Mine is stuffed with dryer sheets, after reading this I may have to go add some more... in the frunk.