Actually whether replating or anything else a shop will need to remove some brass before starting the plating ---as a cleaning step -- This is true of REPLATING, but not RELACQUERING. Replating can have much more effect on the sound than relacquering. A proper relacquer would not remove any of the metal. Be careful though, as there are a lot of BAD relacquer jobs! I've had a couple horns relacquered. What they did was the disassemble the horn. I had the sterling silver keys polished and otherwise left alone on both the Conn horns that I had relacquered, The body was then soaked in a citric acid solution that removes ONLY the lacquer. The horn is then chemically cleaned and buffed, carefully relacquered, and then the body baked to cure the lacquer. It's a factory quality finish, and it looks original. I would not relacquer a horn unless much of the lacquer was worn off and the horn was starting to oxidize. I worry about the brass pitting.