Is there anything special I need to do to care for my powder horn?
Yep, great recommendation here! I live in the PNWet and my horn is scrimshawed (by me) and I keep it with a light coat of Johnson's Paste Wax. Works well and have had my horn since 2014 when I made it.If its scrim or stained, you can wax it. Wax the wood as well.