I learned a new trick for getting a Parker "51" cap to let go of the jewel without breaking it. I got a rather beat up pen of eBay that had a loose clip, and for the life of me couldn't get the jewel to turn.

So, thinking that the plastic must contract more than the metal inside screw, I tossed it in the freezer and left it there a couple days (mostly because I forgot about it, to tell the truth). Tonight, I pulled it out, stuck the jewel up against a rubber stopper, and it screwed right out.

Nice surprise. Now the clip is tight (although I forgot to put some tape on the cap, so the shiny ring is larger than it was, but it's rather dented anyway) and the jewel is nicely installed. Used some folded up masking tape to screw it back in, the stopper didn't work so well going back in.

Peter