Cleaning wooden doors

This is posted on behalf of a colleague offline

    What is the best way to clean exterior wooden doors? These doors
    are coated with the grime of use and exposure to the elements.
    The exposure includes bird droppings. The doors may have been
    painted or varnished at one time, but there is little evidence
    of that now--they are approximately 400 years old and exist in
    rather harsh conditions--arid climate, hot summers, cold (some
    snow) winters, and in more recent years, heavy pollution. Any
    suggestions as to how to approach this problem. The current
    inclination is to use a lye solution. This occasioned my
    colleague's question, as it seemed an extreme treatment. I think
    there must be something that is not so harsh for cleaning and a
    reasonable way to protect the doors after cleaning. Any
    suggestions?

M. Susan Barger, Ph.D.
Department of Earth and Planetary Sciences
University of New Mexico
Albuquerque, NM

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                  Conservation DistList Instance 13:22
               Distributed: Thursday, September 30, 1999
                       Message Id: cdl-13-22-020
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