Melissa,

I have many years experience in the conservation of silver and have
treated literally many hundreds of historic silver objects.

In my experience the rate of silver tarnishing can be quite variable -
the environment plays a huge part as well as the "type" of silver, its
method of fabrication, and previous history in use and cleaning.

If you do not experience high rates of tarnishing in your region or in
your bulding then buying lots of silver cloth may not be cost
effective. If you have moderate to high rates of tarnishing then using
silver cloth as a storage choice is prudent - because every time you
polish a silver object you are wearing the surface and also may be
leaving residues behind that can cause problems more serious than
tarnishing. I have seen some piece of historic silver that have
literally had all the details polished away and with polish residues
that cause permanent loss of surface due to etching and corrosion.

Silver cloths work because they contain materials (such as copper
thread) that react to the sulphur in the athmosphere and react with it
before it can contact the silve object - there is also a line of
anti-tarnish plastics with reactive copper than was developed for
sensitive electronics that you can make into ziploc bags that works
very well (static intercept).

When conservators do testing using replicant metal coupons / objects
we accelerate the effects of ageing by employing elevated temperatures
(just as Marc so nicely described) and also by adding elevated
relative humidity. Most of the things that you are trying will not
outgass sulphur rather working by direct contact (I once had a silver
object where the loose lid was held on with a rubber band, leaving a
black stripe etched across the surface). Also there may be fairly
significant air excahnge in the cooler that you are using. I would
suggest going to small scale testing such as we commonly do in
conservation, using test tubes, metal coupons (and yes the preparation
is critical!), and by adding 1 ml of water, then hanging the coupon
from the stopper, and also adding a source of sulphur (actually wool
works rather nicely), and then putting them in a lab oven at elevated
temperature, you should see results within a week or so.

Cheers!
Dave

David Harvey
Conservator
Los Angeles, CA

On 10/1/07, Melissa Thompson <[log in to unmask]> wrote:
>
>
>
>
> We are conducting an experiment to determine whether or not the price of
> silver cloth is relative to its tarnish prevention abilities.  We have three
> pieces of newly polished non-museum silver.  One is wrapped in the expensive
> Pacific Silver, another is wrapped in the cheap Joann Fabric silver cloth,
> and the third is the control piece not wrapped in anything.  We want the
> pieces to tarnish and are trying to accelerate the process.
>
> The conservator we have consulted suggested putting the pieces in a box to
> control the air that has access to the objects.  We are using a cooler.  She
> told us that sulpher is a tarnishing agent and we have to introduce more
> sulpher into the air.  Her suggestions were egg yolks, moist matches, and
> rubber bands.  These have not tarnished the silver at all and we have been
> working on this for two months.  Does anyone have suggestions on how to
> quickly tarnish silver or another way to test this hypothesis?  Has anyone
> ever done anything similar to this?
>
>
>
> Melissa Thompson
>
> Collections Assistant
>
> Vesterheim Nowegian-American Museum
>
> 523 W. Water Street
>
> Decorah, IA 52101
>
> 563-382-9681 x242
>
> www.vesterheim.org
>
> [log in to unmask]
>
>
>
>
>
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