Alec300SD has made a good list.

If removing the wheels support the car on the suspension, not the frame with the wheels hanging.

Fully charge the battery and keep it charged if it is doable safely. Don't let the battery freeze.

Clean the car of every possible crumb of food to not attract mice.

Can ultrasonic rodent repellents be used in the storage area?

Slack the tension on the window mechanisms as slightly as possible.

Treat the weatherstripping with GummiPflege.

Add biocide to the fuel to prevent vs. remove fuel organisms.

Good luck!!

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