Deb,

What you describe is electrochemical cleaning, where you set up a
galavanic reaction between two dissimilar metals in the electromotive
series in an electrolyte solution to allow the current to flow. The
metal that is the cathode (-) will become stripped and if the reaction
is allowed to continue then it can actually erode tiny pits and holes
into the metal. This technique is used sometimes in conservation but
very carefully and only usually for more problematic metal treatments,
as it is more aggressive, and actually destroys patina, and can cause
uneven surface appearance. Often silver treated this way will have a
dull matte appearance and is then polished again to try to restore the
bright surface. By using this technique you are essentially exposing
fresh atoms of metal to the air to react and reoxidize or corrode, as
any stable oxides have been removed. This also tends to destroy
historic surfaces. We control this technique in conservation by using
applied DC current via a DC power unit with fine controls - so we can
locally electrolytically clean a very aggressive spot of corrosion
with a handheld electrode, for example, or do the overall cleaning but
at a much lower current that is monitored and adjusted. I am much more
likely to employ this on a problematicve iron, tinplate, or bronze
piece than I even am on a silver object.

Basically, this is nothing I would really advise someone to mess with
unless they have some non-collections, non-heirloom metal objects in
the garage that they want to play with. Usually the electrolytes are
caustic so you've got to wear rubber gloves and you also have a
hazardous disposal issue too.

Cheers!
Dave

David Harvey
Conservator
Los Angeles, California, USA

On 11/1/05, Deb Fuller <[log in to unmask]> wrote:
> Dave,
>
> Just out of curiousity, I remember a lady in my old church who had a
> silver cleaning pan which was I think made of magnesium. I forget what
> you fill it with but all you had to do was dunk your silver and it
> came out clean. I think she also used like borax and aluminum mixed
> together in a glass jar which did something similar.
>
> Do you know of these methods and would they be safe for historic pieces?
>
> Thanks!
>
> deb
>
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