Care for Moldy Leather-Bound Books

Terry Collins, a book binder and book repair expert at Salem College and a regular C2C workshop participant, provided the following guidance to another participant.  Because many more of you may find his advice useful, we’ll post it here.

 When mold is attacking the paper:

Dry the book out, as best you can.  If the spine is fairly sturdy, you can open it fanlike for drying.  Make sure you have a good amount of air circulation—use a fan or take outside for a short period.  Once the mold is dry, vacuum with a soft natural bristle brush, brushing from the direction of the spine toward the vacuum nozzle.  Keep the nozzle an inch or two away from the book and cover it with gauze or nylon netting to prevent sucking up loose pieces.  Vacuum the inner hinge area too, as mold spores like to rest there. (and discard the filter afterwards.)  When working with moldy objects, it’s always a good idea to protect yourself with a NIOSH-compliant respirator.                                 

Interleaving with blotting paper, every few pages, will help draw the moisture out of the book.

Always try vacuuming first before other treatments.  Without getting into technical treatments that require a fume hood, collections managers can LIGHTLY moisten a paper towel with 70% isopropyl alcohol (rubbing alcohol) and wipe down areas like the inner hinges, and the head and tail and fore-edge of the text block.


  1. If the paper cockles, then the towel is too wet.
  2. Test a small area first to see if the alcohol causes the ink to run.
  3. Discard the paper towel wipes frequently.
  4. Do not try and wipe the “fuzzy lumps” of fungus, it will spread and stain the paper.  (I think mycologists call the “fuzzy lumps” mycelia).

Drying, alcohol, and freezing treatments all kill active mold, but the spores are just waiting for favorable conditions to return and start up again.  So, preventative measures are the key.  Remember to try to keep RH below 65%.  Archival products like acid-free boxes and silica gel can buffer humidity changes and protect the storage micro-environment from excess moisture.

When mold is attacking leather:

Leather, too, can be wiped with isopropyl alcohol.  But one has to be careful.  Any added moisture can stain or cause dye transfer.  If the leather has rotted to a condition known as “red rot”, then the alcohol will darken the leather and make it brittle.  There is chemical treatment for “red rot”.  But red rot cannot be turned back into leather.  The chemical composition of the leather has changed. Basically, the sulfuric acid used in the tanning process has deteriorated the leather into dust.

Thanks to Terry for sharing his knowledge.  Since nearly all cultural heritage collections contain at least some books and paper, his tips are really useful.



About collectionsconversations

This blog will contain posts from the C2C project staff on a variety of topics related to collections care and disaster preparedness. Enjoy the posts and let us know if you would like additional information or have a topic you would like for us to address.

Posted on August 11, 2011, in cleaning, collections care, Connecting to Collections, disaster preparedness, guest bloggers, workshops and tagged , , , , . Bookmark the permalink. Leave a comment.

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