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Besides my occasionally used auto door locks, I have the same problem with seldom used home door locks.

You may be able to get them to turn with regular lubricating oil. If you use a penetrating oil first, once loose, give them a shot of lubricating oil. I've been using PB50 lubricant, same company that makes PB Blaster penetrant.
BTW, WD40 is not a good penetrant or lubricant, use something better for both needs.



Actually WD40 is great for frozen door locks . "WD" stands for "water displacing" it literally moves it out of the way.