Cleaning plaster

We have acquired a large plaster relief mural that has been
displayed in an artists studio for approximately 50 years.  As the
studio was largely unprotected from the elements, the mural is very
dirty, and potentially moldy underneath the layers of dust.  While
much of this dirt can be removed simply by brush vacuuming the
piece, there does appear to be some staining, particularly from the
ferrous nails that were used to hold it on the wall.  Other than
these stains the plaster is in good condition, the surface generally
appears stable and cohesive.

Does anyone have advice on cleaning plaster beyond brush vacuuming?
In particular wet, solvent or poultice methods that have been used
successfully.  Any advice on stain removal would also be much
appreciated.

Helen Privett
Objects Conservator
National Gallery of Victoria


                                  ***
                  Conservation DistList Instance 15:1
                  Distributed: Wednesday, June 6, 2001
                        Message Id: cdl-15-1-017
                                  ***