In alt.home.repair, on Wed, 26 Dec 2018 07:37:28 -0800 (PST), TimR
wrote:

Graphite can cake up into a mess with any humidity. I did use it in locks years ago and it worked well temporarily.

Now I've been using a drop of STP on the key and a squirt of WD40. That combination has been effective so far. STP is magic stuff, it clings to anything. Including your hands, you can wash multiple times and still have it on your fingers.

I don't know about washing STP but in general Boraxo Powdered Hand Soap
is the best. Mechanics' waterless cleaners are good too, but they don't
seem to be by the sink.