Been here, done this.

The ONLY was I was able to get them out was to use a big-ass Black Diamond "cam" (size #4, I think), which in this case is a piece of rock-climbing equipment. A prybar didn't budge them by itself. Once I got the cam in and THEN got the prybar aroud the back of the cam, I was home-free.
It's the only way I figured out how to do it and yes I tried WD-40, swearing, screwdrivers, robo-grips, screaming, meditation, Voodoo, the Force, etc. for close to an hour until I came up with the above screwy idea...
It worked, though. If you've got a friend with a decent rack of climbing gear, you may be saved.