Number Three – Mold and insects
There are always mold spores floating around in air, so if your books are in a warm, humid place, you can safely assume that mold will be growing in them soon. If it isn’t already. The air doesn’t have to be warm for mold to grow if the air has a very high moisture content, as you may have seen in some refrigerators, but I admit, the likelihood of the air around the average person’s book collection being that high, is low. But stagnant air will certainly increase the chances for mold development, so, as mentioned in my previous Healthy Books post, make sure to keep your books well-ventillated.
Mold stains paper very quickly, and it is next to impossible (if not actually impossible) to get most mold stains out of paper. Mold can also weaken paper, and if it is left to its own devices, it can take over and erase pictures, and even eat away the actual paper. I have seen a book where the mold made several consecutive pages inseparable. There was no paper left in that area, just one big lump of mold.
Now for bugs. My first encounter with the bugs/books combination was as a very naive, newly-arrived Texas resident. I put a box of books in a storage unit off my porch (climate very much not controlled), and when I looked in again a few months later, the roaches scattered, shocked at being disturbed from the feast they had been enjoying for so long. After my shrieks died down, I noticed that the leather cover on my great-grandmother’s traveling letter case had been eaten, along with the glue that held it together, and many pages of the other books had their corners eaten. Roaches do not mess around! Silverfish, termites and some beetles also enjoy a tasty meal of paper. Insects tend to prefer warm, dark, damp places, so keep your books off the floor, try to keep the temperature cool, and make sure your books aren’t near any plants, or food particles.
Just as a final fyi, bird and rodent droppings are also bad for paper, as they are corrosive.