Raw brass can also be a sign that the original lacquer on the horn degraded to the point that the owner couldn't stand the appearance any longer and stripped it all off in order to get a better looking and uniform surface. Now you may wonder, "Why strip it off and not just re-lacquer it?"
The answer is that stripping is a bit of work, but re-lacquering is HUGE effort. Not so much in applying the lacquer itself, but in preparing the surface, which must be meticulously buffed and then degreased and neutralized. And if any blemishes remain, they'll show up really well under a new coat of lacquer .
When I get the time, I plan to remove the remaining lacquer from my oval euph and leave it raw. Once the horn gets a good patina, it shouldn't be a messy problem to handle it. Also, you can always just polish the raw brass -- like people polish silver. Not something I would want to do.
Gary Merrill
Wessex EEb Bass tuba (DW 3XL or 2XL)
Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
Amati Oval Euph (DE 104, Euph J, J6 euph)
1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
1947 Olds "Standard" trombone (Olds #3)