Working as a locksmith in Roseville California I can’t tell you the number of times that I have been called out to a job because a key was no longer working and all that was needed was a little lubrication in the lock cylinder.

So take it from a professional locksmith if your key has been working and then all the sudden stops, the first thing you should try, before calling anyone out to fix the problem, is putting a little lubricant in the lock.

Locks are composed of movable parts when you slide your key into the lock cylinder the blade of the key pushes up a series of either wafers or pins. As time progresses elements such a dust and corrosion (caused by hard water) can cause the movable parts to stop moving freely. When this occurs your key can stop working.

By spraying a little lubricant such a Tri-Flow or even WD-40 into the keyway of the lock cylinder you diminish the friction that is binding and preventing the pins and wafers from moving freely. If this was indeed the reason that your key stopped working,  then after applying lubricant, it should begin to work again.

I also advice that you apply the same lubricant to the latch as well as the bolt that comes out of the edge of the door; lubricating these parts can make the door both  open and close and even lock more easily.

If your key still does not work after applying lubricant then it may indeed be time to call out a professional such as California based Roseville Locksmith.