Please do not follow Mr. St. Clair's tip on cleaning brass or copper with
vinegar, salt, and flour.  Pots and pans perhaps, but keep acid (Vinegar)
and especially salt away from any museum brass and copper, even on a train.
If the salt/acid solution is not washed off THOROUGHLY, it will lead to
serious corrosion, especially in areas where it has dripped and penetrated
that one may not be able to see.  Never-Dull is better for brass on
locomotives, but not great for decorative art brass.  The best idea is to
polish the brass once more, then apply a lacquer like Incralac so that
future frequent polishing will be unnecessary, although it will be
necessary to re-lacquer evert 10 years or so.   Rick Kerschner, Shelburne
Museum