Plaster reliefs

Saye Khajeian <khajeian [at] yahoo__com> writes

>We are working in a mosque that belongs to 300 years ago and there
>is fine decorative art, of gypsum. For some reason its surface is
>covered by oily germs of candle.  Does anyone have any idea that how
>can I treat this? I think ammonium or acetone can clear these germs.
>If I do that, does the gypsum soak it and make it darker? Physical
>methods are very slow and scratches the surface so, I prefer not to
>use them.

Why would you want to remove that oily layer from relief surface?
Maybe it was part of an preventive program at the time of the
decoration (we have many examples of this in Iran). If you are
certain must be removed you can use dimethyl formamide; I think it
will work.


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                  Conservation DistList Instance 20:21
                Distributed: Wednesday, October 18, 2006
                       Message Id: cdl-20-21-006
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