Vintage Synth Repair

Well, not exactly vintage really, but I've got a couple scratchy pots
on my microKorg and can't get the damn knobs off to get inside the
dern thing. They don't have any screws in them to untighten and I've
put a fair amount of pull on them to try and pull them off, but
they're either glued or stuck on there with some other method that
isn't particularly obvious.  It was a floor model i bought from a
friend at Guitar Center when they first came out and didn't even have
any in stock yet, so I imagine maybe they have a policy of gluing them
on so people cant rip them off...Any suggestions on what the best way
would be to get them off so's I can get in there and replace them?
Thanks,
Ti_