Hi Paul, and welcome to APUG! You're right, it's a great forum.

When I lost a rewind crank from a Ricoh, I stuck a dentist pick into the hole, angled it to catch the ring that has to be lifted to open the back of the camera and pulled up. Just about anything that is stiff, strong and hooked enough to catch on the way out should work. I haven't had to break into the Canons in my stable yet, but I don't think there is much difference.