If you want dents removed in brass then take it to a band instrument
repairman.  The nickel plating was Watts nickel.  It is a bit duller
finish than most platers do today -- they actually make the nickel
plate brighter by adding a brightener to the solution.  Saccharin
sweetener is the additive to make nickel look brighter.

By the way, stop buying your musical instruments on the Internet or
there will be no band instrument repairman to take instruments for
repair.

Don Teach - Shreveport Music Co.
Shreveport, Louisiana