Jim,
I used the same finish I do for pens, the homebrew friction polish that was on the forum a few months ago. I use laquer instead of shellac though. Then I used a 2 part resin/hardener to seal the quarters on top of the stoppers.
Thanks to everyone for all of the comments. Wait until later and I will be sharing another idea for bottle stoppers. They are turned and are setting up as we speak.