http://algebraoflife.blogspot.com/20...nnis-ball.html

Cliffs: burn a hole in the tennis ball, about the size of a screw driver. Put the hole that you put in the tennis ball upto the lock, hold it on tight and crush the ball. The air coming out of the ball make the lock, unlock.

Don't know how it defeats the extra step of having to normally turn a key, but I'll try it.