[Jeff Chandler]

Don’t use wd40 for locks in winter. Use oil.

I use graphite spray for locks.

[mrsmith]

When I used to have graphite spray at work it was great for locks and lots of small lubrication jobs. Not enough use for it around the house to justify it now.

And I should have mentioned to lubricate locks by putting the oil on the key. A drop off the dipstick is convenient.