Drying and Cleaning Wet and Moldy Volumes

Collection Management Procedures

June 2023

Goals

  • Thaw and air dry volumes that were stored in a freezer after a water emergency

  • Remove inactive mold from thawed volumes

  • Return volumes to storage

Supplies Needed

  • Paper towels/Newsprint

  • Blotter paper

  • Corrugated board

  • Bungee cords/twill tape

  • Book truck

  • Nilfisk GM80 mold-designated vacuum 

  • Soot sponges

  • Hake brushes

  • Biosafety cabinet

Health and Safety

The following PPE is strongly recommended:

  • Nitrile gloves

  • N95 respirators (non-valved)

  • Plastic aprons

Procedure

Setup

  1. Line the base of the biosafety cabinet with blotter paper or newsprint.

  2. If any volumes are not already in a plastic bag, put them in a plastic bag and seal the bag. If any plastic bags are not sealed and can be sealed, seal them.

  3. Set up an empty book truck next to the biosafety cabinet for compressing volumes once cleaned and mostly dry. 

  4. Set up a standing fan near the biosafety cabinet.

Step 1: Air dry volumes1

  1. Remove a maximum of four volumes from the freezer and transport them to the biosafety cabinet on a book truck. 

  2. Place the volumes inside the biosafety cabinet, leaving them in their plastic bags. 

  3. Turn the biosafety cabinet on. 

  4. Leave the volumes for 24 hours to acclimatize and start to thaw. 

24 hours later 

  1. Remove the volumes from their plastic bags and discard the plastic bags. 

  2. Stand the volumes upright underneath the biosafety cabinet with at least the front and back boards of each volume fanned open.

  3. Ensure the biosafety cabinet remains turned on. 

  4. Turn on the fan to increase air circulation.2 Aim the fan away from the drying volumes.  

  5. As the text block continues to thaw throughout the day, separate and fan open pages. 

End of the day

  • If not completely thawed, turn volumes head to tail and fan open additional pages that have thawed.

  • If volumes are thawed, but still wet, interleave every 15 pages or so with paper towels or newsprint. Complete the interleaving by placing clean blotter paper inside the front and back covers. Close the volume gently and place it flat on several sheets of paper towels. Change the interleaving frequently. Turn the volume from front to back each time it is interleaved.

  • Leave volumes to air dry overnight.

The next day 

  • If the volumes are almost completely dry, see Step 3.

  • If the volumes are still wet, repeat the steps in the section above. 

Reminder: Wetness can persist inside the volume in the gutter, along the spine, and in the boards. Pay close attention to those areas when checking the volumes.

Step 2. Press non-moldy volumes

Leave moldy volumes in the biosafety cabinet to dry completely. When a non-moldy volume is almost completely dry (i.e. only slightly damp or cold to the touch):

  1. Place the volume on a book truck lined with blotter. Place a piece of corrugated board on either side of each volume and at the front and back of the group of volumes. Interleave blotter between the front and back boards of each volume. Avoid tucking the blotter completely into the inner hinge; place it just outside the hinge line.  

  2. Compress and hold the volumes into place by wrapping a bungee cord around the group of volumes and the sides of the book truck. Ensure that the bungee cord is not in direct contact with the volumes. It should only touch the booktruck and the pieces of corrugated board. 

  3. Leave the volumes overnight. 

  4. The next morning, undo the bungee cord and check if the volumes are still damp. 

  5. If so, switch out the blotter and repeat the compression.

  6. If the volumes are dry, remove all blotter and board. 

Step 3: Allow moldy volumes to dry completely

Repeat Step 1 as needed to air dry moldy volumes inside the biosafety cabinet. Do not complete Step 2 for moldy volumes. Once completely dry, move to Step 4.

Step 4: Remove mold

Begin mold removal only when a volume is completely dry. Ensure the biosafety cabinet is still turned on. Use a mold-designated Nilfisk GM80 HEPA vacuum along with hake brushes and soot sponges as needed to remove mold from the volume. Work from the outside in. Start with the covers and spine of the volume. Then vacuum the textblock with the volume closed. Then vacuum the inside covers. If you discover mold on any of the interior pages, vacuum them last. 

  1. First, use a hake brush to lightly brush the mold into the nozzle of the vacuum. Do not vacuum the volume directly. 

  2. Once you have vacuumed the entire volume with the brush, vacuum it again using a soot sponge to loosen any additional mold.

  3. Once all mold is removed, store the volume with the other dried volumes on the book truck.

Step 5: Return volumes to division

  1. Once all volumes are thawed, dried, and mold is removed, coordinate with the curatorial division to return the volumes. 

References

NEDCC 3.12 Freezing and Drying Wet Books and Records. 

Mold: Detection, Response, and Recovery training workshop. CCAHA. January 18, 2023, Stephen A. Schwarzman Building. 

The Preservation Directorate of the Library of Congress.

  1. Repeat as many times as needed. ↩

  2. Turn off the fan before leaving for the night. ↩