As a small child I had a similar problem, with a bar end plug. I tried poking it with a bit of wire and got nowhere, so as it was close to November time I utilised my higher brain function and carefully doctoring some firework
Five or so bangers, a rocket, and air bomb I packed the resultant powder into the opposite bar end with a "steely" to act at a kind of bullet to pop the bar end out.
Jammed the handle bars between two branches on a tree, and lit the fuse from the end of a cigarette. It worked, the bar end was no longer jammed in the handlebar. Never found it, or the steely.
Well not for about five or so years. When I was on my way to school, and noticed a "steely" embedded in the tarmac of someone’s driveway. It was either as a result of someone driving over it when the tar was fresh and wet. Or as it was in direct line of sight of the tree I'd fired it from. But about 300m away.