Q&A for How to Keep Car Doors from Freezing Shut

Use any product containing silicone. It usually comes in a spray can. Apply around the door frame and lock.

I've used it, and it has done the job, however it's likely to mess up your clothes as you brush against it getting in and out of your car, so wipe it down with a paper towel after applying so there's only the lightest coat on there.

Yes, you can use Crisco oil. Apply to gaskets but wipe with paper towel to remove excess oil.

Alcohol will evaporate more slowly when it's cold. Chances are, you'll be able to get the key in the lock before the alcohol is gone.