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Removing sulfides


I have a bunch of small copper parts that I want to remove the
patina from (I’ve used ammonium sulfide to darken them). I’ve
read here on Orchid and elsewhere that if you place a sulfide
darkened or tarnished object on a piece of perforated aluminum in
a bath of baking soda and water, the sulfides will dissolve.
Well, I tried this today and lo! it didn’t work. The solution of
baking soda was pretty strong and warm, the perforated aluminum
was clean. Is this all a myth? And if it is supposed to work,
can one of you explain the chemical principle involved? What did
I do wrong??

(I suppose I could go out and spend money on Tarnex or some
commercial cleaner, but it wouldn’t be as much fun.)

Thanks for your ideas -

Rene Roberts


It’s not a myth- I use this trick to clean my silver. The
problem might be that you need washing soda, not baking soda.
Washing soda is sodium carbonate rather than sodium bicarbonate,
and can be found in the laundry detergent section of many
supermarkets. As for cleaning copper, when I was a kid I used
to clean copper coins by putting them in a little Worchestershire
(SP?) sauce, which ate any tarnish off them in a matter of
minutes, and left the coins so clean they were pink. I have heard
that catsup is also good for cleaning copper and brass. I’m
thinking it’s the combination of acid and salt in these
condiments that does the trick.