Removing of insect droppings from paintings

Has anyone come across a successful method for the removal of insect
droppings from paintings? The paintings in my care are often
unvarnished and covered with lots of fly and possibly other insect
excreta. I have come across two types of droppings: black and beige
in colour. Sometimes they will dissolve when treated with water or
other aqueous cleaning agents. However, most of the time, they
remain solid. There does not appear to be any correlation between
the colour of the faeces and solubility,

I do not know whether I am dealing with varying ages or different
insect types. Obviously mechanical removal with a scalpel is not
ideal as they tend to have fused with the paint layer and when they
are removed mechanically, they take some of the paint with them. Any
suggestions would be very welcome.

Bettina Ebert
Paintings Conservator
Asiarta Foundation
Malaysia


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                  Conservation DistList Instance 25:4
                   Distributed: Monday, June 27, 2011
                        Message Id: cdl-25-4-021
                                  ***