What is the prefered method of cleaning the pipe's rim? I have heard of anything more elaborate than spit and cloth. Is there a way, a solvent, or solution that can be safely used to clean rims without harming the stain or wood of the rim?
Use spit to lubricate a razor blade as you carefully shave off the gunk, and then when you have the bulk of it off, just use the regular spit/coffee and a rag. I also have a piece of medium shag carpet tacked to a board for rubbing the rim on before racking. I started this when I accidentally found that rubbing my pipe rim on the floor really cleaned and polished the rim well. But, then my wife caught me... so the carpet remnant on a board prevents flying frying pans. YMMVI am looking for big removal of year's worth of stuff.