Keyboard replacement, how to get rid of those remaining bolts?

When you replace the keyboard, one has basically to rip it off the TOP case. What is left can be seen on the picture: https://www.dropbox.com/s/0yj1tkr1hz5kty...

Stupid, little bolts, some have been ripped of with the keyboard, some are stuck. I tried removing them with pliers, that worked in some cases, but often the bolt just sets half cut, still sitting in the Top case.

Does anybody have an idea how to get rid of those bolts? So I can finally screw back the new keyboard?

Thanks!