The brand name I'm using is Penofin (marine grade). It's main purpose is for wooden boats, but I figured a few years ago that if a boat can withstand water with this finish, why not a call. One of our local lumber yards carries it here. Runs about $35 per gallon. You can soak it just like teak oil. All of my calls have had the same treatment. Wet sand on the lathe, using the oil, with 600, 1000, and 2000 grit sandpaper. Soak for 24 hours in a thinned-down solution. Remove, wipe it off and let it dry for a few days, then soak for another 24 hours in full strength oil. After it dries for another day or two I hit it with the buffer and Tripoli. The one drawback, as with any oil, is to make sure you don't have any drips hanging on the edge of the call while it dries (really gums up). Hope this helps.