Detecting water damage in less than a second

Once a book gets wet, it’s likely to develop mold.  Even if its now apparently dry, some damage has already been done and you generally want to avoid them all together.  A dousing also is a lot more obvious than a book that’s just been kept somewhere damp for a long time.  When you’re quickly perusing a large pile of books and deciding which to take, you often don’t want to devote the time to individually opening and examining each one in detail. First you want to make a quick cut, then take a second look.

These are tip offs that you should either take a a little closer look at a book or immediately move it to the “no” pile.  Once you’re skilled at this, you may be able to sort books as fast as you can pick them up.  These are tips for when you have hundreds, or even thousands of books to sort through to decide what you want.  Unless it’s something you KNOW is still worth buying even with water damage, these tip offs will general land a book on the reject pile right away.


The first and most obvious tip off that the book has gotten wet is the SMELL.  There’s no mistaking the smell of mildew.   Do a quick sniff test and determine if it’s the container or the books that smell off.  Sometimes it’s simply the cardboard box they were carried in that smells off and the  books are fine.  Simply removing them from the container will be enough to defunk them.  Even if it IS just the box, this is generally a tip off the person didn’t consider them good enough to pack carefully, so consider it a warning to pay careful attention to what you’re looking at.



The most obvious sign it’s gotten wet is warping (as seen in the photo with this post).  You can get swelling and warping like that front a book that sat on a damp (but not wet) floor as well.

Speckling on the cover is often another sign it got doused or was kept somewhere damp.  The cover will have lots of little white or colored speckles on it.  This is where the cover delaminated and stuck to another surface, often the book next to it. This can happen if they’re packed on a shelf somewhere somewhat damp, so the interiors MAY be fine.  But generally unless it’s something  that you have people beating down your door to buy, the visual damage will make this a no go.



When you pick up a book that got wet and dried it will feel different than one that’s been kept correctly.  Books, even hardcovers, have a slight amount of give to them when picked up as the cover and pages slide against each other in your hand. If they’ve gotten wet and then dried, they lose this give and don’t move properly as you pick them up.  You’ll feel a slight stiffness or hitch to the book moving in your hand.  Different types of paper have more give to them than others, so with very old books, you may get a lot more give, or a lot less, than you’re expecting because they use a different type of paper.

Squeeze the book slightly as you pick it up.  It should feel solid with only a slight amount of give that should be uniform across the text block.  If it feels uneven, with patches that are harder or softer, it’s probably gotten wet.

A book that’s gotten wet may also feel rough on the cover, where the cover has partially delaminated. You’ll be able to feel the original finish, plus an all over roughness like it’s been scraped across something.



Sound? Book don’t make sounds!   They do if they’ve gotten wet! This goes in hand with the feel.  A book with any warping or that got wet and dried will crackle slightly when it’s picked up or squeezed.  The crackling noise will be most evident when squeezed.  It sounds different than the sharp, clean crack you’ll get from opening a book that’s never been opened. Sometimes it’ll sound more like a sliding noise than a sharp crack. It depends on how much it was handled after it dried.



Please don’t lick the books. HOWEVER, if you’re unsure on whether a book smells off or not, you can sometimes inhale through your mouth to check for mildew and taste it that way. YUCK.


These tells don’t eliminate the need to look at books individually and evaluate them, but it can help streamline the process so you immediately can sort out the definite nos from the maybes when you’re confronted by hundreds of volumes at once.  Now get scouting!



4 thoughts on “Detecting water damage in less than a second”

  1. One note – I have had to explain to volunteers (I’m at an archive with rare books, but a lot of our volunteers are retired public librarians) that just the existence of cockles doesn’t mean water damage per se, and that actual water damage (as in, you know it’s been doused, because you were the one who took it out from under the leak in the roof!) doesn’t necessarily mean mold. (I wash my hair and air-dry it, which takes a few hours (thick and long), but it doesn’t get moldy, because there aren’t mold spores there to grow to begin with.) Finally we had a really humid day, and I was reading a paperback outside at lunch – came in, and the pages were all wavy. Showed a volunteer; showed her again an hour later after it had re-lost the moisture in our dry stacks. She’s now a bit pickier about what she tosses in the “aack! mold! put it in the trash!” pile.

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