I've got a Kryptonite cable lock that the same thing happens to. I just use a graphite pencil to color in the blade of the key, and then try to unlcok. The graphite helps the tumblers, almost like a lubricant. Put the key in a few times, turn, take it out, and start over. Ihave never had my cable lock not come off. Just keep tryin. The first time I had it happen I just walked away from the lock, went back 20 minutes later, and it worked fine. Maybe I was the problem, who knows.