I think this was a part of my problem for sure haha...
I just spent another couple hours on two stems, mostly with a magic eraser, toothpaste (as a mild abrasive) and a damp rag. It definitely helped a lot with one of the stems (top in pic). I could polish it up more for sure, but it doesn't stink as bad now and looks half decent. The other stem (bottom in pic) still stinks, and the surface texture still feels granular and gritty. Maybe it just needs more elbow grease, but the other one looks way better from the same treatment.
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Top stem in it's pipe, an old very well used Savinelli brushed bulldog.
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