Sootmaster sponge

In Conservation DistList Instance 10:18 Mark Vine writes:

>Smoke sponges are made of vulcanized rubber, they are not toxic and do
>not contain any chemicals or additives. . . . it does contain some
>traces of soap.

Raw rubber is vulcanized (hardened) by heating it with a chemical
agent, usually a sulfur compound. When I looked at natural rubber
erasers (also made from vulcanized rubber) a number of years ago,
there seemed to be significant amounts of active sulfur compounds
remaining in the finished product.

Also, archivists are familiar with the sticky black accretions that
appear on the pages of old ledgers, residues from rubber eraser
crumbs that were not brushed away, and with deteriorated rubber
bands that stick to paper and bindings.

These observations suggest two precautions for the use of chemical
sponges for cleaning up soot:

    1.  One should take meticulous care to brush away all crumbs
        that flake off the sponges.

    2.  The sponges may not be appropriate for objects that are
        sensitive to sulfur compounds, such as photographic
        materials. A photographic conservator may wish to comment on
        this issue: does a brief exposure to vulcanized rubber
        and/or its residues create lasting damage?

Shannon Zachary,
Conservation & Book Repair
University of Michigan Library

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                  Conservation DistList Instance 10:19
                 Distributed: Thursday, August 15, 1996
                       Message Id: cdl-10-19-004
                                  ***