I find myself to be completely disinterested in museum cards, and horns?? Even less so. I'll give you any that I have if you would like. I don't even know how many that is. Never looked. I'm about 250 game days or so.
I do have 10 (maybe more) of the tank horn, #112 is it?
The only drawback is if I am limited to trading a total of 5 paints or horns per day we have a problem as i gift paint and trade it regulalry. If i can send 5 Paints AND 5 horns per day we are in business.
I honestly don't know. I've never sent any horns, only received the tank ones and gathered others as I play the game.
I don't see me using them to be honest.