Need tips about removing gas cap

[B. W.]

I agree with BILT4ME, if the key operates correctly then the linkage (mechanism, whatever) that attaches to the locking bolts is broken. It may be possible to drill out the lock cylinder without drilling all the way through the cap, this will prevent most, if not all of the debris from entering the tank. This may allow access to the locking bolts or may allow them to move freely. All of the locking caps I've dealt with are non-ferrous (pot metal?) so sparking should't be an issue. Maybe LockDoc can chime in on sparks when drilling out a tumbler?