Brass has been a common finish since the nineteenth century. It is a warm but relatively high maintenance finish, requiring frequent polishing to keep it shiny. Even with constant polishing, unprotected brass will tarnish (brown spots) in time. For some, the tarnish is desirable. Natural brass is supposed to tarnish so obsessive renovators might prefer unprotected brass.
For more information about unprotected brass and other finishes, please see Finish Tips.