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How to Remove the Mildew Smell from Books

Five Parts:Why Books Smell Mildewy or MustyFixing Immediate Sources of DampnessUsing an Absorbent to Remove OdorsHiding the OdorFuture Storage

Old books are wonderful treasures to find and can even be worth money, but they come with a musty smell as well. Here's how to remove or reduce that mildew smell.

Part 1
Why Books Smell Mildewy or Musty

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    Check dampness. Dampness, wetness and soaking of a book is the primary cause of mildew or mustiness in a book, providing an ideal growth medium for mold, bacteria or fungus (which all smell bad). Regardless of the cause of excess moisture left on books, moisture causes pages to stick together and nurtures mildew. Dropping the book in the bath causes total havoc, and leaving a book next to a damp wall causes gradual mildew growth. Storage of books results in bad odors from mildew. If you don't know whether the book has been wet in the past, telltale signs include:
    • Pages stuck together (especially the edges), but it can be the whole way through. Chunks of pages can be stuck together, leaving others to freely turn.
    • Discoloration; brown or black speckling, yellowing.
    • Mildew or mold growing on the spine or cover of the book, especially if the book is old and the cover is made from organic material, i.e. leather or paper.
    • Mildew or musty smell, like a damp cellar/basement.
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    Cigarette smoke damage. Another cause of musty odor is exposure to cigarette smoke. Books will look yellowed, speckled (brown spots running up and down page edges and often across inner pages of book; also known as "foxing") and there may be a stinky smoky odor as well as a musty one, depending on how long the book was in the smoky location (being absorbent, book paper can stink of cigarette smoke for years).

Part 2
Fixing Immediate Sources of Dampness

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    If upon picking up the book, you can feel it is damp and see wet or damp pages clumping together, deal with it immediately. The longer a book is left, the harder it will be to fix and the more likely mildew will grow.
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    Stand the book upright on a table. Fan out the pages gently. If your fingers can't disentangle pages without ripping, use a letter opener and tweezers to separate. Alternatively, blow into the pages from the top to fan the pages out. Apply one strip of adhesive tape over the fan to keep the pages separated.
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    Let stand to dry in a warm spot free of moisture. Ensure that every page is nice and dry.
    • You could try direct sunlight if the book isn't valuable. However, direct sunlight may fade the book, and especially for older, valuable books, could lead to disintegration, discoloration and curling up of the pages permanently. Warmth but not direct sunlight is the best approach.

Part 3
Using an Absorbent to Remove Odors

It's assumed that by this stage, you've dried the book and you want it to be odor-free so it can be read. Remember, dust introduced by these methods may linger in the book and cause damage down the line.

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    Try silica. You can purchase silica from an arts and crafts store.
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    Try kitty litter. You will need a large container, like a Rubbermaid tub and a smaller container, as well as an absorbent, like baking soda, cat litter, or charcoal.
    • Fill the larger container halfway with kitty litter.
    • Place the smelly book or books at the bottom of the smaller container. Place the container above the kitty litter inside the larger container.
    • Seal the larger container tightly, and leave the book to sit in the absorbent for a few days.
    • Check every few days. If the odor has gone, remove the book or books and dust off (a new paint brush is ideal for dusting). If not, repeat until the book smells better.
    • Store in a clean, dry place to avoid reintroducing mildew.
      • Activated charcoal or charcoal briquettes can be substituted for kitty litter in the method outlined above. Just be careful not to bring the book into direct contact with the charcoal or it may sustain blackening marks.
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    Try baking soda. Place a cup of baking soda into a plastic box or bin. Place the book or books (this method is good for more than one book) inside and seal the lid well. Leave for 48-72 hours, then check. Repeat until the odor has gone.
    • Another approach if you live where it's dry heat and sunny: Sprinkle baking soda between the pages, perhaps every 10 pages or so. Leave the book open in the sunshine for a few days in a row, turning pages often (bring in at night). Sniff to see if it has improved and continue until it smells better. This won't work on all mildew or musty odors, but it can be helpful for some. (Be sure not to leave the book exposed to wind or rain.) This is not advised for valuable or antique books, or those already showing notable page yellowing or brittleness; it may make the book's condition worse.
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    Place newspaper between the pages. Place a sheet of newspaper between every few pages of the book. Do not use on valuable or old books, only cheaper ones (newspaper is acidic and it may transfer ink to the book).
    • Scrunch up balls of newspaper and toss inside a resealable plastic container or bag.
    • Place the book in and cover with the lid.
    • Leave for 3-5 days.
    • Remove all the newspaper. The book will, hopefully, smell better. Do not leave books wrapped in newspaper, as this can harm the book long-term.

Part 4
Hiding the Odor

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    Sometimes, no matter what else you have tried, the odor lingers. You can try to mask the smell and hope that it makes reading the book bearable. Note that none of the following should be done with a valuable old book as perfumes and chemicals can introduce elements harmful to the book's paper. A musty or mildew odor might be better than ending with a crumbling book!
    • This is not an approach that will preserve the book. In fact, the below approaches may damage the book if used long-term.
    • If this is something you will try to conserve, you will need to consult a professional.
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    Use fabric softener sheets. These sheets absorb odors from fabric and they can do so for books, too. Again, the oils in dryer sheets can damage books, so be mindful when using this method. Try the following:
    • Cut a bunch of sheets into thirds, and put one between every 20 pages or so in the smelly book.
    • Keep the book in a zipper bag a few days, then the musty smell should be gone.
    • This method is good for "preventing" the musty smell of books as well––just put a piece of a fabric softener sheet in every fifth book, or so, on your bookshelf.
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    Cut a small square of fresh, fragrant drawer liner. Place inside of book. You may like to use 2-3 pieces, depending on the size of the book.
    • Place inside a resealable plastic bag. Let sit in a dry spot for a week or two.
    • Check now and then to see if the fresh odor has been transferred to the book. Continue until the book smells better.
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    Use strong essential oil. Add drops of an essential oil like lavender, eucalyptus or tea-tree oil to cotton balls. Place in a resealable plastic bag. Add the book and seal. Remove after a few days. The book should smell like the essential oil. Because of the risk of oil spots, only do this with less valuable books that you want to read, such as moldy-but-useful textbooks.

Part 5
Future Storage

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    Check storage areas before storing books. The storage area should be dry, not too hot and not too cold, as cold encourages dampness and heat dries out paper, causing it to crumble. Excessive humidity is bad, so find storage with low humidity or reduce the humidity. Do not place plastic containers in direct sunlight or near heat sources where they may develop condensation, which would drip onto your stored books!
    • Ensure bookcases are not against cold, moldy and damp walls.
    • Check the attic or basement for leaks, mildew and dampness.
    • Check storage facility for bad odors and signs of mildew or dampness before signing up to storage.
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    Use appropriate storage containers.
    • Choose plastic boxes if the storage area is prone to leaks or dampness. Also, add silica gel sachets in case of condensation.
    • Don't over fill bookshelves. Ensure adequate air circulation between books.
    • Add clear dust jackets. These keep moisture away from book. It's easier to replace dust jackets than the book cover or its binding.


  • Protect valuable collectible books (rare comic books or an antiquarian volumes) in bags made of polyester (e.g. Mylar). For short-term storage, polypropylene or polyethylene; these are available from book dealers, comic book stores and online retailers in many sizes. Inclusion of a 100% acid-free backer board (replaced every few years) helps to leech acids out of books and extends "lifespan."
  • Strong odors, including mildew, acidity, smoke and pet smells, can be hard to remove. Months of setting these books open on a table with frequent dusting and page turning, or (for hardbacks with good bindings) sitting upright on a shelf with pages fanned open, will gradually reduce odors.
  • Place a damp book in a container with silica gel packets. These are a desiccant and come in shoe boxes and new purses.
  • Try Microwaving for 10 to 15 seconds. Take the book out. (Caution: It may be hot, use a potholder!) - repeat a couple times if necessary. No longer than 15 seconds at a time, then let it cool!
  • Thymol may destroy book mold, but it requires special application. Seek instructions from a bookseller that uses it.
  • You can't change the color of a book from yellow back to white. Yellowing or browning is due to acids in the paper which eventually cause deterioration, which leads to an acrid odor and brittleness. Consider having the book digitized if it looks like it's falling to pieces and is not available online from Google Books or Project Gutenberg. Yellowing isn't necessarily a cause of musty or moldy odors unless the book has been exposed to excessive light and heat. All books have unique scents and perhaps one of the above methods can improve a bad smell.
  • Not all musty odors are due to mildew or other contamination. If a book shows no signs of water damage or staining and came from a smoke-free environment, but still smells like sour basement, the acids in the paper may have been excessively oxidizing. Books, up to the end of the 20th century (and low-end, mass market books still today) use paper containing residual acids in it from the manufacturing process. Acid-degraded paper odor is inevitable, due to age and exposure to heat.


  • Avoid prolonged direct sunlight and other heat sources (radiators, storage in metal sheds) and bright light sources (plant grow lamps, halogen lights near bookshelves). These drastically accelerate damage from the paper's own acids. Heat and light also accelerate colors to bleach, binding glue to degrade. A day or two won't cause harm, but even one week on a table that receives direct sunlight is enough to noticeably fade book covers, and intensify the acidic mustiness of an old book.
  • If the book is a valuable collectible, don't do anything before seeking out an archival preservation or book restoration specialist for professional advice or services. Better safe than sorry! Local dealers in rare books are a good place to start. Never apply tape, glue, cleaning fluids or anything else not specifically advised for book restoration, or irreversible damage may result.
  • When using cat litter as an absorbent, use low-dust litter. You do not want dust to infiltrate the spine or binding of the book. Also, keep cat boxes away from bookshelves because cats track soiled litter onto and into nearby books. Litter box odor can gradually infiltrate books and be difficult to dissipate.
  • Bleach and other household or industrial cleaners damage and destroy books.
  • Be careful with silica packets if you have pets, especially cats. Dispose of silica quickly and securely.
  • While excessive moisture can lead to contamination problems, excessively dry pages in older books tear more easily. Do not keep books in too dry an environment. Freezing has a drying effect; it is another enemy of books. If your books must go to a storage unit, make sure it comes with baseline climate control.

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