Cleaning mounted birds

Roberta Salmaso <mcsnat [at] chiostro__univr__it> writes

>I am looking for information (personal experience or bibliography)
>on how to clean mounted birds, mostly from dust, sometimes very old
>dust. I know that this can be done with a light washing,
>trichloroethylene, dimethylketone or lac thinner.

The first thing to determine with any kind of mounted animal skin is
the presence of arsenic. The older the specimen is, the more likely
it is that arsenical compounds applied to the inside of the skin
during preparation have migrated to the outside of the skin. Don't
do any cleaning until you know about this. Steve Williams and Cathy
Hawks published on this in a back issue of _Leather Conservation
News_. Check the bases of the feathers as well as the skin surfaces
around beaks and glass eyes (sometimes even the surfaces of the
glass eyes) for a white microcrystalline substance. Williams and
Hawks recommend a testing procedure. Merck also makes an arsenic
kit, but recent reports indicate that they do not endorse its use
for museum or conservation purposes (I need to find out more about
this, as it is a useful test for presence or absence of arsenic).
You may also find that mercuric compounds have also been used on some
taxidermy specimens. Both arsenic and mercury compounds were
intended for use as general biocides to keep pest damage down, but
they constitute human health risks today. If they are present, you
must take steps to protect yourself (fume hood, gloves, respirator)
before you proceed with cleaning.

If you can remove part or all of the dust manually (gentle brushing
and pinpoint vacuuming through a screen), do that in preference to
the use of solvents. Feathers normally have some natural oils which
many solvents will strip, leaving them more brittle. Some feathers
will readily lose pigment coloration in solvents (though
structural/prismatic coloration is less affected). Some taxidermy
mounts were also painted to restore life appearance, and you may not
know this until the paint is removed by a solvent. All skin surfaces
(feet, legs, beaks, skin around eyes, and featherless skin areas
such as vultures' heads and necks in some species) have been painted
by some preparators. So use solvents only as a last resort.

Often dust on bird taxidermy mounts is held in place by grease
migrating from poorly-prepared skins (don't even ask me about
ducks!). Use gentle solvents and take your time. I'd start with
simple distilled water and see if that solves the problem, using
barely-damp swabs. If the dust is stubborn, I'd move up to
non-denatured 70% ethanol. I haven't found any dusty taxidermy
specimen yet that needs anything stronger. Don't immerse the
specimen in anything or leave it wet. Don't wet the skin unless it
is a featherless area, and, if you wet unfeathered skin, be sure you
dry it thoroughly. Birds have very thin skins and any moisture will
wick easily through to whatever the taxidermist used as a form,
which may swell and split the skin. This is especially true of older
specimens, which were often mounted on wrapped straw. (Taxidermy
specimens are not "stuffed" like children's toys, so don't go
looking for sawdust.)

Finally, if you do determine that the specimen has arsenic or
mercury compounds, be sure that you document that for future users'
sake. Some places use a special tag (often colored red). You don't
have to panic--the specimen will not leap out and kill you--but you
should be able to identify such specimens easily and to have
separate handling and use policies for them. Good luck.

Sally Shelton
Director, Collections Care and Conservation
President-Elect, Society for the Preservation of Natural History Collections
San Diego Natural History Museum
P.O. Box 1390
San Diego, California  92112
619-232-3821
Fax: 619-232-0248

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                  Conservation DistList Instance 10:49
                Distributed: Thursday, November 21, 1996
                       Message Id: cdl-10-49-003
                                  ***