Brass discoloration? ? ?

My cleaning lady cleaned a very old and lovely brass lamp that belonged to my mother. Whatever she did, it looked fine at first, but now green stuff is gathered in the creases of the embossing. In one or two places, it is starting to turn black. I managed to rub away most of the black and some of the green with a toothbrush, but not all, and it is tedious.
Any ideas welcome. Would vinegar and salt help?
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She may have used a paste polish or cleaner with ammonia or chlorine in it.. Either one will react with the copper in the brass, if the lacquer is worn off in places, and produce either copper chloride or another salt, most of which are colored green. There are some good care hints at www.englishcustompolishing.com/usca/brasscopper1.html which i found on Google. Basically, you could use a small soft brush or rag, hot water, and mild detergent to get all the traces of of green off, then use a fine brass polish *very* sparingly, and follow the instructions above. The engraving tends to hold any compounds, so some care must be used in completely removing all polish trapped by the grooves.
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Ray wrote:

So are most cleaning ladies....

You didn't say whether you want it to look "bright and shiny" or "antiqued". If you want the former, then you'll have to get it spray lacquered after its polished, or learn how to lacquer it yourself.
If you're willing to settle for it turning darker with age then yes, vinegar and salt will help take off whatever's eating away at it now, but make sure you wash it off quite well when you're through cleaning it.
HTH,
Jeff
--
Jeffry Wisnia

(W1BSV + Brass Rat \'57 EE)
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You describe tarnish, though the colors sound as much like copper as brass. There are plenty of brass cleaners in the supermarket, just pick one and follow the directions. After is is clean, you can buy a brass sealer (hardware store, maybe drug store) and it will stay looking clean and shiny.
If it is an antique, consult an antique dealer before cleaning again to be sure you are not destroying its value by removing the patina.
Vinigar and salt is exactly opposite of what you want to do. It will accelerate and cause the tarnish.

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