Removing soot from plaster and silver leaf

I am an objects conservator in private practice.  An artist I know
recently has had a layer of fine particle, silt-like soot deposited
on about 20 paintings that include (burnished) Venetian plaster and
silver leaf (due to work on a chimney).  The soot adheres to
surfaces and smears if brushed.  I don't have experience with this
condition.

My thoughts so far: treatment must avoid pressure and abrasion to
avoid compression and spreading of the soot into the porous surfaces
and abrasion of these delicate surfaces.  Treatment must also avoid
rubber/sulfur-containing products such as Absorene soot sponges and
broomstick to avoid tarnishing the silver leaf.  I would appreciate
learning of additional treatment method and material suggestions and
concerns.

I am also researching conservation assistance resources for artists
in this situation and would appreciate suggestions.

Jenny Dennis


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                  Conservation DistList Instance 29:29
                 Distributed: Sunday, December 13, 2015
                       Message Id: cdl-29-29-018
                                  ***