Red Green wrote:

Recently had to have a key made for van door lock I had no key for.
Locksmith lubed the lock and it wasn't graphite based. I asked why
and he said because of the high humidity here in the mid-south
graphite is NG. When combined with moisture it hardens like cement.
Have to take his word for it. Well established locksmith. Not some
matchbook cover graduate working out of garage and car.

I was told years ago (by an experienced locksmith) not to use graphite on
locks.

What did he use? WD-40!

...and the WD-40 thread war is on again :-)

Not a bad cleaner for some purposes, I wouldn't count on it to actually
lubricate anything.