Erasers

I stand corrected, per Mark Vine's discussion with the manufacturer of
Skum-X, and apologize for any confusion which I may have caused.
Unfortunately, I my glibness overcame fact. I did not mean to imply that
there are beach sand size granules in there, or cause a panic. And given
the forum, readers understandably took me quite literally. I was under
the mis-impression that the Skum-X contained silicates (ground up sand,
if you will) as an abrasive cleaning aid and filler, as do many of the
other commercial powdered/crumbed eraser brands (loose or pad form). The
citation previously listed (Paper Conservation Catalog/Surface Cleaning
Outline published in 1992 ) lists CCI's analysis of Skum-X (CCI ARS
1738.11), on page 18, as: "polyhydrocarbon rubber and calcium carbonate,
with indications of the presence of sulfur, possibly chlorine, and
possibly traces of aluminum, titanium, silicon, and zinc; The pH of
aqueous solution is basic. Relative amount of tarnish is very heavy."
(tarnish on a silver coupon under the test conditions). In fact, Skum-X
was the only loose crumbed eraser product tested by CCI which did not
contain silicates. However, the above information does not change either
the general informational content or cautionary note about using erasers
on photos in my original message.

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                  Conservation DistList Instance 8:77
                  Distributed: Tuesday, March 21, 1995
                        Message Id: cdl-8-77-005
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