Earthen wall decorations

I am working on earth structures in Iran. I want to preserve a
wall of earthen decorations like stucco of gypsum. These decorations
are from about 600 years ago. Which consolidant do you propose I can
use in this case?


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                  Conservation DistList Instance 17:43
               Distributed: Wednesday, November 26, 2003
                       Message Id: cdl-17-43-020
                                  ***