Keeping the bugs out

New anoxia treatment at the Conservation Lab

An important part of Preservation Strategies’ role at the University of Miami Libraries is to keep the bugs out. Otherwise, it’s a feast of nutritious cellulose in the stacks.

Recently at the Conservation Lab, we received two items with evidence of insect activity: an artist’s book and a painting. The artist’s book, “Simple Verses,” is a uniquely illustrated and handwritten scroll, featuring one of José Martí’s poems. It is made of paper and fabric adhered to a wooden folding fan, hand-crafted and decorated with feathers and colored media. The painting is from the Ana Gloria and Vince Oller Collection and is a portrait of Ana’s sister, Juana María Borrero, painted in oil on stretched canvas.

As we examined the book, we identified the presence of insect frass and checked to see where it was coming from. We found tunnels dug out of the wood, and before we knew it, some very hungry termite larvae. Although we didn’t see signs of living insects in the painting, erring on the side of caution, we decided to treat the painting as well.

**Above:** (Left) “Versos sencillos/Simple verses,” illustrated and designed by Rolando Estévez Jordán (Ediciones El Fortín). (Right) Tunnels created by termite larvae at the base of the wooden folding fan.

Freezing is a key preventive measure to mitigate possible insect damage, but it is not always the best course of action. Different types of materials can swell or shrink at extreme temperatures in different ways, which can cause bonds to shift and paint layers to crack.

For the two objects here, we decided to try a safe alternative treatment known as “anoxia.” We placed the objects in a bag made of a barrier plastic and then removed the oxygen from inside using “scavengers.” The scavengers use the same technology as glove warmers and heated back wraps: they are packs of iron fillings that absorb oxygen in the air and release heat. The heat, however, has the potential to create humidity; it is the perfect environment for condensation, mold, and even keeping the bugs alive. To prevent this, we included packs of silica gel and a relative humidity (RH) indicator. Finally, we used a vacuum to remove as much air as possible and heat-sealed the final seam of the enclosure.

**Above:** (Left) Conservator Duvy Argandoña heat-seals the enclosure with a tacking iron. (Right) Anoxia chamber after air removal.

During the next two weeks, we will monitor the oxygen and humidity levels closely. As we wait to inspect the results of this project, we will explore more widespread use of this technique for our varied collections. As the University Libraries continue to collect more artists’ books and a wider range of materials, anoxia will be an important tool for us.

**Above**: A prepared anoxia chamber with oxygen absorbers, conditioned silica gel, an oxygen monitor, RH indicator, and padded paper trays.

For additional resources about Integrated Pest Management for Cultural Heritage visit:

“Canadian Conservation Institute (CCI) Notes 3/1”
https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/preventing-infestations.html

Integrated Pest Management Working Group
http://museumpests.net

“Northeast Document Conservation Center (NEDCC) Preservation Leaflet”
https://www.nedcc.org/free-resources/preservation-leaflets/3.-emergency-management/3.10-integrated-pest-management

What’s Eating Your Collections
https://www.whatseatingyourcollection.com