How to unscrew this lid?
The lid on this cup is stuck. The lid itself is made of two pieces - the outer part (which you can see in photo 1) is metal. But this is really just a metal cap over an internal black plastic piece (visible at the edge where the cup and cap meet in photo two) that has the screw part on it.
They used to move as one, but whatever tab/connector inside caused the plastic ring inside to spin when you twisted the lid has worn down. So when you go to spin the lid, the metal part moves but the plastic part doesn’t. So the cap is stuck on.
Obviously the cup is old and we could just get something else to replace it. But it’s a cherished cup (for various reasons) so we would like to get it to work again.
Once it’s off, I think I can glue it well enough to work again for a while, though suggestions here are appreciated.