Mold

Stuart Bagley <sbagley4227 [at] sbcglobal__net> writes

>Does anyone have information on ways to decontaminate moldy
>documents? Is it even possible.

When removing mold from documents you must first assess if the mold
is active or not. If the document is still wet and supporting mold
growth, it must be dried out before removing the mold. This can be
accomplished by placing the documents in an area of 50% or lower RH
for several days, or placing them in microenvironments with silica
gel. Cleaning can be accomplished with low suction and a HEPA
vacuum, using a soft brush to lift the mold up off the paper into
the vacuum nozzle, avoiding scrubbing motions that can cause damage.
If the mold damage is significant you may still be able to vacuum
with very low suction with the document secure under a fiberglas
screen.

The reduction of mold and mold spores is the goal of this activity,
and realistically cannot remove all of the mold spores and
fragments. Some spores and fragments (and some staining) may remain
in the paper fibers, so the documents need a stable environment to
be housed in, avoiding peaks in RH. If you test the inks on the
papers for sensitivity to ethanol and the inks are stable, you can
use a 70-80% ethanol solution with deionised water to gently spray
down the documents to dry out the mold. (I'm not sure if you can do
this with parchment papers or not). However, these documents must be
monitored in the future because some molds are actually activated by
solvents like ethanol. In past research, myself and others have
found that mold can grow in a variety of solvents. When cleaning the
documents, you may want to use a Class II B2 Biosafety cabinet
instead of a fume hood, to avoid contaminating your fume hood and
it's duct work and to avoid cross-contaminating everything else you
put in your fume hood after the moldy documents. A biological safety
cabinet is different from a fume hood in that it is specially made
to prevent biological materials from escaping the cabinet into the
room. This is done with a special flow of air through HEPA filters
that create a 'sheet' of air where the user's hands enter the
cabinet along with negative pressure to prevent air in the cabinet
from escaping. Fume hoods have a different level of suction and a
different path of air flow. Many folks are currently using fume
hoods to deal with cleaning moldy collection materials, but this is
not ideal; fume hoods become contaminated in the ductwork and cost
lots of money and formaldehyde to decontaminate, and they cause
cross-contamination of other collection materials placed in the fume
hoods because the fume hoods are not sterilized.

Biosafety cabinets are stainless steel surfaces that are sterilized
with a built-in UV germicidal lamp that is switched on every night
and wiped down with sterilizing agents. If you do not have one in
your lab, you can likely make an arrangement to use one at your
local university biology department. You may also want to sterilize
the brush and HEPA vacuum microattachments after use with bleach and
water. Some folks have skin reactions to mold, so it's best if you
use nitrile gloves to protect your hands when handling the
materials, along with a N-95 type dust mask so you don't breathe
spores that can irritate your lungs.

Amber Tarnowski
US Army Military Heritage Museum and Education Center
Carlisle Barracks, PA


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                  Conservation DistList Instance 18:57
                  Distributed: Wednesday, June 8, 2005
                       Message Id: cdl-18-57-008
                                  ***