Cleaning metal threads

I am working on an early twentieth century military uniform with
tarnished metal wires on the epaulets.  The epaulets, which can be
removed from the rest of the uniform for cleaning, have silver and
gold plated copper alloy (possibly brass) threads couched down with
a waxed cotton thread to cotton velvet, wool, and a stiffening
fabric.  The silver metal is black and the other metals have a
greenish corrosion product on the surface.  I would like to brighten
the metals and remove some of the loose surface corrosion products.
The threads and fabrics are all in good condition.

After reading through various approaches for cleaning metal threads,
the use of a water, perchloroethylene and non-ionic emulsion with a
soft brush described by Timar-Balazsy and Eastop or an
electrochemical method seem to be gentle to both the metal and
fabric elements.

I would like to know what experience other conservators have had
using these approaches.  Were you happy with the cleaning achieved?
Did you see any kind of redeposition back onto the metal or fabric?
What, if any, long-term affects have you seen to the metal or fabric
elements?

Rebecca Tinkham
Conservation Department
Museum Services Division/DCA
PO Box 2087
Santa Fe NM 87504-2087, USA


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                  Conservation DistList Instance 19:52
                  Distributed: Friday, April 28, 2006
                       Message Id: cdl-19-52-015
                                  ***