Same process as Tony. I seal mine after polishing, inside and out, with my special sacuce. I've found the real crappy part of working with horn is sanding and cleaning up the inside. You will end up with cuts between your ring and middle finger almost every time. Inside the horn, since you cant really buff it out, it is best to sand with the grain to about 400 grit wet. This will usually look nice and will get 90% of the smell out of the horn. It also allows light to pass through the thinner horns giving you some really nice patterns and color. "Finished" horns with crud still in them shows a little bit of lazy IMO.
Trashcan
Death Card Calls