Removing shellac from plaster of Paris

Kate Roberts <kater [at] tawera__monz__govt__nz> writes

>Is it possible to remove old discoloured shellac from a work in
>plaster of Paris and recoat it to look as the artist intended?

I would recommend a 50/50 mixture of acetone/ethanol.  For best
results mix the two solvents together first and immerse the object
(in a closed solvent-proof plastic container or plastic bag).  Leave
for 1-4 hours.  A light brushing and/or swabbing should remove
residues.  Rinse, or repeat if necessary.  Poulticing or simple
swabbing is less effective.

Note: *Always* wear gloves when using this mixture of solvents as
the mixture is much harsher on your skin than either solvent
individually.

Stephen Koob
Department of Conservation and Scientific Research
Freer Gallery of Art
Smithsonian Institution
Washington DC 20560
202-357-4880 x276

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                  Conservation DistList Instance 9:16
                  Distributed: Monday, August 14, 1995
                        Message Id: cdl-9-16-004
                                  ***