And, to finally get to the point (your question) ... with one cap that I killed
(broken lead) and later autopsyed, I tried putting it in the nice Jacobs chuck
of my electric drill, and using a small knife blade as a lathe tool.  I was
actually able to remove a significant amount of metal before I slipped and
impaled the condenser membrane.  I'm encouraged enough by this experiment to
seek out a real lathe with 1/4" collet and see if I can make a tool that will
curl the metal chip out to the front.  This might actually be easier than
disassembling the capsules.