Not wanting to give up, I managed to remove the glued-in pipe cleaner using various drill pits and other pointed objects. With that done, the stummel got a thorough sanding. Sanding the rim here with 400-grit to remove various scratches and burn marks.
Wet sanding with 190-proof alcohol (Everclear). 400-1000 grit. I like using Everclear as a sanding medium because it evaporates quickly. Briar isn't very absorbent anyway, but the alcohol works better than water for this purpose.
Removed from the booze bath, it's ready for buffing. Sometimes I'll add a little color--leather dyes and such--but this time I just buffed with Tripoli compound, followed by White Diamond and then wax.
This was the grungiest, greenest stem I've worked on in a while, and I doubt it's the original stem for this pipe. It still needs some work, and the interior of the stummel will need to be repaired. All in all, however, this is an interesting exercise. The pipe is a Theydon 9130, a GBD "second".