Unfinished Brass has not been professionally finished. It is brass left in its natural condition, after the manufacturing process. The appearance can vary. Unfinished brass may be dull, bright, tarnished, have small scratches or be covered with a thin film of grease.
Dirt, slight oxidation and fingerprints can typically be removed with a solution of 50% lacquer thinner and 50% water. Small scratches can be removed using fine steel wool. Brass can then be shined with brass polished or stained with a darkening patina. Lacquer is often applied once the appropriate finish is achieved to maintain it. If lacquer is not applied the brass will oxidize - darken over time.
Polished Brass is brass with a shiny finish. The brass is not lacquered and will darken/age over time.
Polished & Lacquered is shiny brass with a lacquered finish. The lacquer seals the brass to keep it shinny.
Antique Brass is brass with a darkened finish to look old.