You could try "raking" the cylinder. Take a thin piece of flat metal (approx 1/8 wide by 1/32 thick maybe 6" long, bra underwire is about right) bend it into an "L" shape and put a 90 deg. twist at the base of the long leg. Slip the short leg into the bottom of the key slot and put a little pressure on the long leg (like you are trying to turn the key slot clockwise with it, the long leg should bend easily) then with another short wire (I use a straightened out paper clip with a 1/8 bend in the tip)insert to the depth of the key, lift up, and "rake" the pins quickly outwards. Gently on the turning pressure. If it doesn't let go, release pressure then put pressure back and rake again. Keep raking and you just might get it to let go. Worn cylinders work better for this. Doesn't always succeed but with luck and patience you may just "pick" it. Once it turns you can pull the cylinder out. Failing that, its a drill or a locksmith (or Magnum P.I.).