I'd unscrew the binding post nuts as far as possible, and try to pry/push it out through the hole in the side with a small punch or a big needle or something. If you get it up a little bit, you should be able to screw the nut back down and get at it with some pliers.
Broken banana plug and stuck in amplifier
Hi, seek your advise how to remove the broken banana plug which is half-broken when i pulled out the plug, it's rather hard to clamp as it leaves a little metal.
The binding post of amplifier (E280) is unable to unscrew fully and to be removed,
Appreciate if you have similar experience and how to remove the remaining banana plug out from amplifier .