i dont know the condition of the metal but i do know air horns are no where near the size of a wheel but i sanded my Zx 6 spokes with like a 150 then a 250 then a 400 or some numbers like that, basically rough, medium, then fine paper and then applied alot of mothers polish and elbow greases and got a mirror finish, i bet you could be parting your hair in those air horns in no time if you went the sand/polish method. Oh yea and its like a $10.00 project