Just finished cleaning and polishing all of my horns which have a silver plate finish. On the advice of a friend, a light coat of "Turtle Wax Ice" was applied to the horns. I was told that this will make finger prints less of an issue, and will also retard tarnishing. Sure hope this works as I just spent half a day doing nothing but polishing.
I'm sure that anything with "Turtle" in it's name must be good stuff.