Hi Caroline,
Thank you for the question. Since this topic is outside my area of expertise, I would like to direct it to someone with more information and experience. One of our experts should be able to get back to you shortly.
Additionally, I would like to provide you with a link to the Smithsonian Museum Conservation Institute, which outlines some basic care information, in case you haven’t already found it. The site suggests how to identify and re-mediate mildew on fabric, and also has good cautionary and safety information. http://www.si.edu/mci/english/learn_more/taking_care/mnm.html