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Dealing with Mold in Your Collections

Stachybotrys Spores

A Love-Hate Relationship

David Fairchild, an American botanist in the late 19th and early 20th centuries wrote about mold in his book, The World Was My Garden (1938, p. 55).

…after my first feeling of revulsion had passed, I spent three of the most entertaining and instructive weeks of my life studying the fascinating molds which appeared one by one on the slowly disintegrating mass of horse-dung. Microscopic molds are both very beautiful and absorbingly interesting. The rapid growth of their spores, the way they live on each other, the manner in which the different forms come and go, is so amazing and varied that I believe a man could spend his life and not exhaust the forms or problems contained in one plate of manure.

Whether he was initially revolted by the mold or the horse-dung is unclear. What is clear is that he eventually found mold to be fascinating and beautiful. As a conservator who is also allergic to mold, I don’t share Mr. Fairchild’s sentiment. When I see mold, I just want it dead and gone.

Unfortunately, this is impossible. Mold is simply everywhere. And, I suppose, I should resist my desire to completely eradicate mold since it does have its benefits. For one thing, live mold promotes the decomposition of dead things, which is why we don’t have dead things constantly lying around. It is also used to manufacture antibiotics and cheese. So, I shouldn’t allow myself to completely dislike mold. However, as it can cause damage to both artifacts and humans, there are some things we should take seriously when it comes to mold.

This plush Stachybotrys sits on my desk, reminding me to be mold-vigilant.

Mold and Our Health

Anyone can have an allergic reaction to mold, even if they don’t have mold allergies. This is true whether the mold spores are alive or dead. If the mold concentration in the air is high enough, allergic reactions will occur in the healthiest people. For that reason, it is important to take precautions when working around moldy artifacts.

My first experience working with mold as a conservator was a little frightening. I was interning at the University of Cincinnati Medical Library and was brushing the mold out of some old books.

Mold in a Book

Each night, I would panic as I tried to fall asleep because I couldn’t breathe! Initially, I didn’t understand what was happening to me or why and was too ignorant to consider going to a doctor. But I eventually connected my health problems to the work I was doing. I searched for protective equipment in the conservation lab and found some coal miners’ masks. These were so thick that they were difficult to breathe through, but they were perfect for keeping the mold out of my lungs! From that day forward, I was able to sleep at night. If you ever need to work with moldy artifacts wear a mask that is rated for mold filtration. Respirators and face masks rated N95 are usually sufficient for this.

Protective Gear
When dealing with moldy artifacts, wear gloves and a mold-rated respirator.

In one of my first apartments, I made the mistake of cleaning the shower that appeared to have been neglected for years. It was full of mold. The next day, I awoke with hives covering my arms! The doctor informed me it was an allergic reaction to mold. In other words, mold doesn’t just affect our respiratory systems or lungs; it can also affect our skin. When working with moldy artifacts, it’s a good idea to wear latex or nitrile gloves to prevent your skin from coming in contact with mold.

Mold and the Health of Artifacts

I mentioned earlier that live mold contributes to the decomposition of dead things. Well, guess what we store in our vaults. While the collection items may have lively stories, they are nonetheless dead things, and mold loves to eat them. As stewards of the collection, it is our responsibility to safeguard the collection against destruction by mold (Dead mold will not adversely affect artifacts but it is not always easy to tell whether mold is living or dead.) To do this, we employ methods that you can also use in your home.

Moldy Paper

Strive to keep your collections at an acceptable temperature and humidity levels. Mold likes to grow in warm, damp environments so store your collections in cooler, dryer environments. To take this a step further you should also keep these items away from windows and external walls where temperatures can fluctuate and condensation can form. Also, because food is a likely place for mold to form, keep food away from these items at all times.

Stachybotrys Spores

As I stated before, mold is simply everywhere and the higher the mold concentration in the air, the greater the risk to our collections and our health. Whenever we open a box of moldy items, and especially when we begin moving those items around, we increase the concentration of mold in that area. This increases the likelihood that mold spores will fall on uncontaminated collection items or that it will cause allergic reactions. If you have moldy items, isolate them from people and other collection items by keeping them in a closed container. Open only as necessary and only when proper safety precautions have been taken.

Unfortunately, the best ways to remove mold are also damaging to our collection items, but there is a way to physically remove loose mold spores from collection items. To prevent mold spores from freely floating through your home, it is best to do this outside. If going outside isn’t an option, make sure your work area is very well ventilated. The process is simple. Dust or wipe down the item using a soft brush, a microfiber cloth, or soot sponge. Ensure whatever tool or material you use is not so coarse that it will damage the item, but coarse enough that it will remove the mold (If you have questions about cleaning specific kinds of collection items, please ask them in the comments section below).

Soot Sponge

Removing mold does not always improve the look of treated artifacts; mold stains often remain. There will also likely still be some mold trapped in the item, especially the more porous ones. But the risk of mold spores escaping into the air will be greatly reduced.


To summarize, mold is everywhere and it can be bad for the health of both humans and artifacts. As such, stewards of historic collections, should take precautions to protect our heath and to keep mold from spreading. To control mold, keep the environment as cool and dry as possible, isolate moldy items from other items by keeping them in a closed container, and remove loose mold when possible. With minor preventive measures applied we can protect both ourselves and our collections so they (both the collections and ourselves) may be enjoyed by future generations.

Christopher McAfee


Why Should You Keep Your Original Documents, Even If They’ve Been Digitized?

History documents the world we live in, provides truth we can learn from, and allows us to maintain a memory of our culture. Without history, we lose the ability to learn from our past and are more likely to make mistakes in the future. Most good history derives itself from original source documents. As such, it is worthwhile, where possible, to save the original source documents in their original form.

Lighting Rooms Where Art and Artifacts are Displayed

Lighting the Rooms Where Your Art and Memorabilia are Displayed

Hats Off! – Supportive Storage

Six hats belonging to the Laraine Day Collection (MSS 2351) have recently come through our Conservation Lab. Laraine Day was a Utah-born actress who became prominent in Hollywood and on television from the late 1930s into the mid-1980s. She starred alongside big names such as Lana Turner, Cary Grant and John Wayne. When the Library acquired her papers, the collection also included some clothing items, including these hats.