I've got a horn, quite old, quite small and not very pretty. It comes straight from the polish cow ;-) And I found it as a very good material to learn - how to prepare a horn. My horn is clean, desinfected and chafed with an abrasive paper.
I knew that a horn should be filled with wax inside, so I bought 3 candles made from beeswax.
I cut the candle along, take out the wick and tear the rest of wax for a small pieces.
I prepare a "hot wash" - so I put some empty pots to the big pot with a boiling water.
Now I use a brush to "paint" my horn inside with the melted wax.
I used only one candle, but it was enough. I made a few layers of wax inside my horn. It looks like on the photo below:
Next time I'm going to decorate the horn, but now I'll check if wine taste better when it's drinked from that horn :>
(*I realized that my english isn't very well - sorry for all mistakes :-) but I hope it's still understandable :-P)