Poultices for cleaning marble

We are working on a white marble statue that was in a public
building, in a public area (not in a museum) and it would be touched
by people walking by.  It ended up with a brownish, greasy residue
on parts of it.  Most of this we have been able to remove using
deionized water and Orvus.  However, we think we can still make it
look a bit better.  Does anyone have any ideas on safe cleaning
agents for marble, or poultices that would help to remove the
remainder of the residue?

Anna Graff


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                  Conservation DistList Instance 25:27
                Distributed: Saturday, December 3, 2011
                       Message Id: cdl-25-27-012
                                  ***