Thought this might fit in with this subject- Had a nice talk with the guys from SEM in Chicago (they're the German company that makes ebonite). They have a two step polishing process to finish ebonite. After shaping and sanding is complete (only to 1000 grit), they have a brown compound used on the small wheel, followed by a yellow polishing compound on the larger softer wheel. After a couple of weeks, I've found that the brown compound doesn't leave a residue unlike some of the green and red compounds I've used before. The yellow compound seems to be a mix of a diamond and carnauba- It's cut my finishing time by 1/3...and the results are better and it works great on polishing briar...The only downside is the small wheel is 35 euros, the large is 40 euros, and the brown and yellow compounds are 40 euros apiece...I think it ran aound $210 with shipping...Another tip that might help- my main motor is a 1/2hp 1750 from an old pipe repair shop- I use a hand tightened chuck on the arbor so I can quickly change out sanding discs or buffing wheels...