Ebonite stem

[jsnake]

Try using a Mr. Clean Magic Eraser. I picked up that tip from looking up info on estate pipe restoration. I used that followed by some polish by Decatur for stems. Worked great for me. If that doesn't do the trick I think the next step was automotive sandpaper but look it up before you try it. I have a system down and there is a really good restoring thread here somewhere.