Key broken off in door lock

My 16 year old son continues to break keys off in locks, switches, what have you. The latest is in the door of my '92 F-150. It's inside the lock and none of it is sticking out where you can grab it or even visible. How can I get it out?

Thanks,
John

Was it straight in when it was broke, or had it been turned. If it was straight, you may be able to use a very powerful magnet to work it out. Otherwise you'd probably have to take the lock apart.

Excellent suggestion. I'll try it. But, on the off chance that he'd turned it some or the magnet doesn't get it out, how do you take the lock apart? Seems like someone told me there was a clip on the inside of the door that released it but I'm not sure if I remember right.