1999 BMW z3 key will not turn the switch?

I had luck using a lock graphite spray direclty into the lock and then inserting the lock and slightly during the wheel over and over again. Lock was "dry". Insert key and try to turn it. Do this over and over again. Put some graphite on the key and insert. Wiggle wheel. Eventually my key turned and that was almost 2 years ago and no problem since.

If you use too much graphite, key will come out of lock black and so you will need to wipe off excess, if any.