Q&A about mold contamination on or in books, magazines, photographs or other paper products:

This article series explains how to deal with mold on books and papers, and what options we have for cleaning or storing moldy books.

Moldy Books and Papers - Can I Save Moldy Books?

These questions & answers about conservation of moldy books and papers or how to clean mold off of papers & books were posted originally at BOOK / DOCUMENT MOLD & WATER DAMAGE RESTORATION - please review the advice given there.

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On 2016-03-18 by (mod) - staged cleaning of items that got moldy while in storag

You'll need to clean moldy items that can be cleaned, such as hard-surfaced furniture, toss out things that can't be cleaned (such as a moldy upholstered couch), and you if they're dry, you might box-up your moldy books in air-tight plastic bins until you can, outdoors, review each one to decide if the book is worth cleaning or if it should be tossd in the dumpster.

On 2016-03-18 by Hopeful?

I hope someone here might be able to help. A moving and storage company stored all of things for over a year in supposedly climate controlled storage - including 5,000+ books - and when the moving company delivered our belongings a lot of the furniture had extensive mold growth on it. Green mold, black and white.

Other items had rust and boxes had water lines. We don't know how to handle a mold situation like this. How would you deal with this? What about the moldy smell from an entire household being stored like this?

Any advice on what to do next would be invaluable. Thank you in advance for any kind of help at all.

This Q&A were posted originally at InspectApedia.com HOME

Reader comments:

(Oct 14, 2012) Peter McMillan said:
Love your web site. Discussion of moldy smelling books very informative.

Question: Are foxing marks on books and paper always caused by mould

(Sept 3, 2012) Rachel said:

Are foxing marks on books and paper always caused by mould or are other factors also at work?

Also, I have a couple of books with shiny pages that have become sticky during a humid summer and have developed orange lines along the edges of some of the pages. Is this a reaction of the acid in the books seeping through the cut edges or could mould be a factor

Question: Chris likes to call book mold mildew - but it's not. Does it matter?

(Sept 8, 2012) Chris said:

As a book collector and once-upon-a-time mycologist I found your web site of interest.
However, I do not believe there would be uniform acceptance among professional mycologists of your distinction between "mold" and "mildew".

The organisms involved are all fungi in the classical sense. Those attacking dead organic matter like cellulose are not all that different biologically from their relatives that may have a preference for the living cells of plants and animals.

The fact that some parasitic species may be facultative heterotrophs (feeding on non-living materials) supports this view.

I believe your cause is best served by promoting the idea that the fungi, a diverse and highly successful breed, will exploit any environment where nutrients and moisture are available whether or not it is living or dead. Books and their bindings in a high humidity environment are sitting ducks.

One final point: since fungi and their spores and hyphae are ubiquitous in nature it should be recognized that there is little chance of getting rid of all of them by any practical means (HEPA filters included).

Since fungi (including species that attack damp books) play such an inportant part in our ecosystem we would be unwise to eliminate them entirely. We can, however, slow them down.

Reply:

Chris,

Thank you for the interesting comments.

I completely agree that all mold is everywhere all the time - and that moisture is a key factor in causing problem mold growth contamination in buildings or on things.

Perhaps it's technical nitpicking, but mildew a subset of "mold" that only grows on living plants. It's among the Basidiomycota, Ustilaginales, and will be either Oidium-Erysiphe Powdery Mildew or Peronosporaceae Downy Mildew.

Mildew, then, It has nothing to do with and won't be found growing on books nor on other building surfaces unless the item in the building is a live or recently-live plant.

See details at MILDEW ERRORS, IT's MOLD

We include the term "mildew" in these articles because of its popular, widespread, if incorrect use as a synonym for problematic molds found in buildings. But if we hear a professed "mold expert" such as a building mold test person or mold remediator insisting on those terms we worry about the person's actual competence and training.

If you were suffering from an operable brain tumor, would you choose a brain surgeon who referred to your brain saying

"I'm gonna chop the dickens out the whatcha-macallit in that thingie inside your noodle" ?

You make an important point, that fungi are very versatile and that many genera/species adapte well to growing on stuff found indoors, including books. On the other hand, if my "mold expert" insists on calling white or light colored molds on books "mildew" it makes me nervous that

- s/he doesn't know much about mold nor mycology

- his/her advice about what to do may involve more opinion than accuracy

You are completely correct that HEPA filtering of air is never a cure for mold problems on books or other indoor surfaces. The effective cure for indoor mold problems involves two basic efforts:

1. Remove the problem mold - this means physically cleaning it off (some remaining stains may be harmless)

2. Find and fix the cause of high indoor moisture or leaks that caused the mold growth and fix those conditions

The reference to HEPA filtration that you may come across in reading about mold remediation in buildings typically involves either a HEPA filter on a machine used to create negative air pressure in the infected area in order to protect other building areas from cross contamination during the period of mold cleanup and repair work, or a HEPA filter used during dust cleaning in other building areas as a means of reducing indoor dust levels without just stirring up worse dust than before.

I also agree with and appreciate your observation that the fungi are a crucial part of our ecosystem - without them and their ability to break down cellulose (not just books, but leaves and dead wood) I doubt that their partner in cellulose decay (some bacteria) would alone be up to the job.

Question: How do I tell the difference between a moldy book that can still spread the fungus to adjecant books, and a clean but stained book that is safe to put back on my shelf?

(Sept 9, 2012) Ellen said:

Thank you for this article.

I have read here and from other professional sources that once a moldy book is dry, mold can be removed with a brush, but may leave a stain behind. How do I tell the difference between a moldy book that can still spread the fungus to adjecant books, and a clean but stained book that is safe to put back on my shelf?

How does a stain look different? And is it ever safe to place a cleaned, formerly moldy book back on a shelf with clean books?

Reply:

Ellen:

You can remove surface mold with a soft brush - work outdoors or using a HEPA vacuum so you don't blow moldy dust around indoors. The stains that remain are often fungal hyphae imbedded in the paper and are not particularly harmful.

By storing books in an area of low humidity, they will be more resistant to new mold growth.

Yes you can return a cleaned book to shelving if it no longer has active mold growth - though in some cases added treatment may be needed if the book SMELLS moldy as those remaining MVOCs are a problem for some people, particularly those with asthma or allergies.

There are a variety of "mold killing" approaches (such as microwaving or freeze-drying) to try to de-mold books but unless the surface, loose, mold growths are physically removed, allergens and pathogens may remain.

Take a look at the references at the end of this article for more in-depth expert sources on moldy book and paper restoration.

If questions remain, just ask.

Question: Reader likes silica gel for moisture protection

(Mar 1, 2013) Alex Funke, ASC said:

Excellent article BOOK / DOCUMENT MOLD & WATER DAMAGE RESTORATION!

However, I would like to point out one incorrect statement.

You refer to using Silica Gel, and say that it may turn into a "soup" which will damage the books.

Too right, and I suffered exactly this disaster. But

The chemical that has this property is Calcium Chloride. It is indeed a very good desiccant, much used in the lab where it is carefull separated fom the material to be dried. It dissolves it into captured atmospheric water and creates a caustic soup.

Silica Gel, however, is totally inert. It captures the moisture and holds it, and does not change its form. You can recycle it to good as new in the oven, if it is in a heat-safe packet.

Silica Gel is the material of choice for moisure protection. I use extensively to store camera equipment safely. Thanks for a great article!

Reply:

Silica gel will not protect books nor anything else from severe moisture conditions.

Question: cleaning mold from moldy photographs

(Sept 18, 2014) Marsha said:

What about moldy photographs? Will these methods work for them?

Reply:

Marsha

The question is one for a photo conservator - which some paper conservators are not. It depends most likely on where the mold is actually found: on the glossy surface of a print it might be simply wiped off. On the back of a photo and not appearing on its face, paper conservation mold removal methods may be just fine. But if mold has grown through paper from the back, a paper conservator's approach may not deal with the problem.

See details at MOLD on PHOTOGRAPHS, CLEAN-UP

Question: how best to dispose of moldy books and papers

(Dec 2, 2014) etcetera23 said:

Hi. I've developed severe mold allergy and (depending who you believe) other mold illness problems as well. Through an ERMI lab test (historical), we determined that our house had dangerous levels of Aspergillus penicilloides, Wallemia sebi, Aspergillus versicolor, and one other I've forgotten.

The lab wasn't worried about the other species. We think that most of the problems arose from a washing machine that overflowed in the basement, which was way too crowded, and that the molds were mostly growing on our possessions rather than on the house itself. There were lots of cardboard boxes full of books, magazines, and papers. Some woods and fabrics, too.

My question concerns disposing of books. I'm a writer by trade, and I have hundreds of notebooks and journals boxed up in storage. None of them shows visible mold. Some of them (depending which boxes they were stored in) are "musty" enough that regular people can smell it. Others are only noticeable to me.

Though it makes me sort of queasy, I'm thinking of having them scanned at a scanning company. But then what? Symbolically and ritualistically, I would love to have a bonfire and really roast 'em, knowing it's hard to burn books and we'd probably have to add gas fuels. (We have a place to do this safely and legally.) However, I read that burning the mold would actually release the spores further, and that many spores are not killed by fire, and can in fact be grown from ashes.

What the heck can I safely do with my old journals? Thanks for any advice you may have.

Reply:

Etc,

You can bag up your moldy notebooks in refuse bags and dispose of them as household trash.

If you want to burn them that's fine, provided your local fire burning cods are met.

Question: saving books and documents exposed to mold

3 January 2015 Desperate said:

The rear of my home was damaged during bad storm when tree fell on it. Lab results show several strains in ceiling,HVAC,etc. I have hundreds of priceless,Photographs , Albums,business papers,etc...that didn't get wet ...but in same rooms as air quality mold tests..What are my options for saving them? Thanks!

Reply:

Desperate:

If books or documents did not get wet but were exposed to airborne mold you can simply wipe or HEPA vacuum them to clean dust and debris before storing those items in a dry clean area. Remember that all mold genera/species are everywhere all the time. A key gating factor in mold growth is moisture. If you keep those materials dry and if they are not visibly covered with dust, debris, or actual mold growth they should be fine.

What you are describing is a specific case of a more general concern: when a building has suffered water damage and mold contamination sufficient to require professional cleaning and repair work, some key steps in that process include:

1. separating and protecting un-damaged materials from the work area

2. establishing dust containment to prevent dust and debris from the work area moving to and contaminating other building areas

See MOLD on PHOTOGRAPHS, CLEAN-UP

Question: silical gel for moldy book repairs?

(Mar 5, 2015) Ryan said:

Silica gel is available at pretty cheap in bulk at places that sell flower and arrange supplies as it's used to dry flowers. If you store your papers in a tub of the stuff for a couple days it'll wick the moisture right out of the paper. You can then line the bottom of your safe with it and it'll continue to keep the contents dry. It can be a bit messy but a plastic Tupperware style container with a bunch of holes punched in the lid or a finely woven sock can stop it from getting everywhere. It may need to be reactivated (low oven for a few hours) occasionally if humidity is the root of your problem.

Reply:

Really?

Silica gel as a dehumidifier or moisture remover is suitable for use in a small enclosure to address small quantities of materials that are damp but not moldy, with the severe warning that if paper or other mold-friendly materials are left wet for more than 24-48 hours you are inviting a mold contamination problem atop the moisture problem.

Where silica gel products are widely and successfully used is as a small packet enclosed in packaging materials for already dry but moisture sensitive materials that are then packaged in an enclosed and well sealed container - such as that new camera that Ryan bought.

On 2019-02-23 by (mod) -

My best advice, more thorough than an off-the-cuff reply here, is in the article BOOK / DOCUMENT MOLD & WATER DAMAGE RESTORATION, Autumn. Please take a look and let me know what questions remain.

On 2019-02-23 by Autumn Pence

My mother stored some of my childhood books in her garage and not long ago there was a leak and some items were water damaged. I was looking through my totes the other day, none of which were water damaged, and noticed that a few of my Dr. Seuss books were molded. Most were just on the exterior, but a couple also have mold on the edges of the pages.

Keeping in mind the "rough" exterior of older Dr. Seuss books, what would be the best way to remove the mold. Regarding the molding on the edges of the pages, what might be the best way to remove that mold?

 

On 2018-10-26 6 by (mod) - are moldy books unsafe?

Ol

I'm grateful that you asked and interesting question, but I have to ask you to excuse me for not being so brazen as to express an opinion about the safety of books in the building when I know almost nothing about either one.

As a general point, if the books show no visible mold and if they don't smell moldy, then it's very unlikely that there is any mold hazard associated with them.

On 2018-10-26 by OL

Our local county library just closed down due to budget cuts. We're in the process of rehoming the books, but some citizens are wary of the books due to a water heater that had been leaking (later replaced) in the building.
There is no visible mold on any books (plus almost all have plastic jackets on.)

There have been two or three mold reports done on the building, and no reports have come back with major concerns.

Do you think there is a hazard with these books? (Some citizens are worried about mold within the pages of the books...)

On 2018-10-10 by (mod) - simple book clean-off

A

If you gently wipe the book exterior and edges while closed, for a book that has no interior mold, I doubt that it's the slightest hazard to continue to use. You might speed the off-gassing and removal of any remaining moldy odor by leaving the book closed in sunlight.

On 2018-10-10 10:50:12.030661 by A

I purchased a used 1943 cookbook off eBay only to find there is green spotting on the edges of the pages, which I assume must be mold. Flipping through I don't see any mold on the pages themselves, or on the cover or dust jacket. For now I have it in a plastic baggie to keep it from contaminating my other books, but is there a cheap way to get it to where it's safe to use (while cooking, obviously) and won't ruin my other books? Buying a fancy vacuum like you talked about would cost way more than just buying another copy from another seller and hoping it's in better condition, which I also can't afford to do. And I don't know if wiping with water like you also mentioned would make it good enough for kitchen use or just for storage. I don't mind if the book doesn't look as pretty when I'm done, as long as it's safe - I bought it for the recipes, not for collecting.

On 2018-01-31 by (mod) - does mold dissolve paper

Ben

usually mold stains rather than devours paper, at least in the short run. But it's true that there are mold species that can Digest paper. In fact molds, along with bacteria are the key organisms on the planet that can break down cellulose - else we'd be buried in a layer of dead trees thousands of feet deep.

On 2018-01-29 by Ben

Does mold on a document simply stain the paper, or does it eat away at it like acid and dissolve it eventually?

On 2018-01-25 by (mod) - freeze then vacuum moldy books?

Carla

Take a look at our discussion of freeze treatments in the article BOOK / DOCUMENT MOLD & WATER DAMAGE RESTORATION. I'm not sure of the freeze duration, especially where no temperature is specified, nor that it is effective for all mold genera/species.

Paper treatments including wiping are also discussed above. I have found wiping, unless a new wipe is used for every stroke, can spread contaminants.

On 2018-01-23 17:11:55.686630 by Carla

@TJ that should have said our mold inspector and it should have said using the brush attachment with a HEPA filtered vacuum cleaner.

Are mold inspector told me to bag up the books in plastic bag and put them in the freezer for a couple days.

All of this using nitrile gloves and face mask and goggles and something to cover your clothing. After the book has frozen for a couple days you take it out using the gloves and goggles and all and you vacuum all the surfaces of the book using the filter attachment with they HEPA filter vacuum.

Supposedly that will take care of it. I feel like I want to wipe the book down with something, but I can't think of anything that would not hurt the book further.

On 2017-05-19 by (mod) - calcium hypochlorite (pool shock) to get rid of book mold?

TJ

I would label the recipe that you gave as both urban legend and in advisable for several reasons. One is that even if you could kill all of the mold in or on a book you are very possibly leaving harmful, toxic, or allergenic particles.

2. It's unlikely that you can kill a hundred percent of mold spores without damaging the book.

3 is that since mold is present always in air anyway, if the conditions that caused the books to become moldy are not corrected, when the books are restored to their environment. Be a new mold problem.

On 2017-05-19 by TJ

I've heard if you place books in an airtight container with an open jar of calcium hypochlorite (pool shock) then seal it up, the CH will kill the mold. Is this true? If so, what is the process?

...

Continue reading at FOXING STAINS on BOOKS & PAPERS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• BOOK / DOCUMENT MOLD & WATER DAMAGE RESTORATION
• PREPARE TO CLEAN BOOKS / PAPERS
• HEALTH HAZARDS, MOLDY BOOKS
• DUST, TYPICAL LIBRARY SHELF CONTENTS
• BOOK-MOLD CLEANUP for DO-IT-YOURSELFers
• MAGAZINE MOLD CLEANUP for DO-IT-YOURSELFers
• MILDEW on BOOKS? - no, it's NOT mildew.
• BOOK CONSERVATION RESOURCES
• FOXING STAINS on BOOKS & PAPERS
• MILDEW REMOVAL & PREVENTION
• MOLD on PHOTOGRAPHS, CLEAN-UP

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INDEX to RELATED ARTICLES: ARTICLE INDEX to MOLD CONTAMINATION & REMEDIATION

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