When we had our key cut at the locksmith he highly recommended using Tri-Flow superior lubricant to clean out and lube the lock cylinder. I put the lubricant lengthwise on the key, insert key, remove key, wipe off, reapply lubricant to key, and repeat until it comes out clean. Then I do the same on the opposite side of the key.

I used to use liquid graphite on the house door locks, but that only lasted a few months before another application was required. With the Tri-Flow the interval has been well over a year before another dose is needed.

 

I voted for silicone lubricant spray, because I trust it not to erode parts and/or gunk up compared to graphite over the long run, from what I've read recently, and because so far I've been too cheap / lazy to try Tri-Flo.

 

I just dip the tip of the door key/ignition key into clean motor oil the car uses, then slowly insert the key in the lock, and wiggle a little, to distribute the oil.

The climate is mild where I live, so only have to do so every few years, if the lock feels "dry" and not smooth.

I do the same for my house's door locks. works for me!

 

Based on the number of locked up ignition cylinders I replace with various liquids dripping out of them, seems like no lube is the best