Dear Judy Knight,
You have already received many great responses, but I am happy to be able to provide even more feedback from a C2CC Community expert, a conservator of textiles and upholstery.
"From your description, it is unlikely that the quilt harbors active or recently active mold. Nonetheless, to be safe, gently vacuum with a HEPA filtered vacuum. You can put a fine net over the vacuum nozzle or the upholstery brush head. A patting motion generates safe, low levels of suction.
As described in a previous response, vacuuming should be done outdoors or in a well-ventilated space, not near collections. For your safety, wear an N95 filtered mask, gloves, and a smock or apron. To echo Mr. Kronkright's answer, air circulation is key. Try to find a place where the piece might hang semi-outside, like an enclosed screen porch or an area where screened windows can be opened. That will help reduce the odor.
Wrapping in microchamber paper may not be practical for such a large object. Activated charcoal might be effective if airing out does not provide a satisfactory result; however, be sure that the charcoal is never put in direct contact with the textile. To utilize charcoal, consider making a container for the activated charcoal and securing it to the lid of an acid-free box or large plastic storage bin.
Please note that it is not advisable to wash the quilt. From the description, the textile sounds fragile. It is a good rule-of-thumb that any large, historic textile should only be wet cleaned by a trained textile conservator. This is in part because the weight of the wet fabric can led to damage. Also, degradation products and soluble dyes can migrate when wet."
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Amanda Kasman
Graduate Fellow
Winterthur/University of Delaware Program in Art Conservation
Wilmington DE
(843) 819-2406
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