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How Do You Keep Old Books In Good Condition?

Any book lover probably has a collection of books of varying ages and conditions. Maintaining old books in good condition will require knowledge of some basic facts about paper, bindings, and environmental factors such as relative humidity, temperature, lighting, and insects. Other factors include position, support of the spine, and weight.

Keeping old books in good condition depends on composition, environment, and other factors. Materials which make up the book, past treatment, and the scope of previous damage affect the condition. The relationship between the book’s value and the cost of proper storage also applies. 

Books are a possession that generally takes up a lot of room in a residence, but which the book lover would not choose to get rid of. As books age, so generally does their condition deteriorate. Here are some tips to help maintain your personal library in the best possible condition.

What are the factors that cause books to deteriorate?

It is unfortunate that improper care of many old books has caused them to deteriorate. In some cases the deterioration has progressed to the point that the book is unusable. Restoration methods tend to be costly and may require materials and equipment that are out of reach for private book collections. These factors all play a role in the condition of the book. Fortunately, catching damage early enough and taking swift steps to combat it can prevent further deterioration in many cases.


Dirt not only detracts from the appearance of your books, it can be abrasive, wearing at the fibers which make up the paper and the binding of books. Particulates too small to be easily seen can lodge below the surface of paper and bindings. The dirt combined with skin oils from human handling and food scraps from poor handling practices can easily scour holes in paper and stain bindings. They can also serve as a nesting place for bacteria, fungi, and insects.


Bookworms are not worms, but the larvae of several types of insects. The insects which are responsible for boring or chewing through books are commonly booklice, termites, silverfish, firebrats, and cockroaches. Some of the larvae feed on mold spores, while other insects are attracted to the starch present in paper and cardboard. 


Ultraviolet light as well as visible light can speed up the deterioration of paper. It also causes discoloration and fading of book covers and dust jacket colors. Even a few minutes of direct sunlight can cause appreciable fading of colors and deterioration of the papers of the book.

Improper storage

Improper storage covers a variety of damaging elements. Books need to be stored so they are supported appropriately. Improper support will cause the spine to become bowed. Books should be stored vertically, with books of the same size supporting each other. Packing them too close together can cause excessive wear when you try to remove them from the shelf. Oversized books can be laid flat on top of the shelves, but not more than three books high.


Books which are composed of cheap quality paper, as is often the case with mass market paperbacks, tend to deteriorate quickly, in part due to the high lignin content of the paper. The cheap paper breaks down because of the acid in the wood pulp. Sometimes noticeable browning is present in as little as a few years. 


Humidity, especially when combined with warm temperatures, causes paper to swell. In addition, books will quickly develop mold and mildew spores. In turn, these spores attract insects, further complicating the deterioration of the paper and bindings. Mold can also affect the health of people and pets in a negative way. 


Warm temperatures create an attractive nesting place for various types of insects and fungi. The combination of warmth, food, and moisture quickly shows damage to books which would otherwise be in good condition. 

Temperature fluctuations

Even mild fluctuations in temperature and humidity can affect the covers and pages of a book. Changing temperatures cause expansion and contraction of fibers. Different materials are affected at different rates. Over time, such variations in temperature can cause warping, wrinkling, and, if excessive, destruction of the book itself.

Poor air quality 

Environmental factors of various kinds negatively affect books. This can be caused by inadequate filtration of interior air, or by pollutants such as cigarette smoke. Automobile exhaust from a busy highway nearby can affect the quality of the air inside your home library. Books absorb many types of odors, including cooking odors and others.

Mold and mildew

Mold spores of various types are always present on surfaces, indoors and out. Many kinds of mold are unsightly, but not dangerous to the health of humans and pets. Other types of spores can be deadly to inhabitants, and harmful to any surface they grow on. The presence of mold indicates too much moisture and warmth, both of which are harmful to the preservation of books. 

Poor handling techniques

Habits which can quickly affect the condition of old books include placing items in the pages that leave stains or indentations and dog-earing pages to mark your place. Using sticky notes, paperclips, or other objects leaves acid residue, rust, and dirt behind. If bulky enough, these items can break the binding of the book and cause pages to separate. Placing an opened book face down on a table or desk can also cause damage to the binding. 

What are solutions for home libraries?

For books in your home book collection, there are some methods which can be used to help protect the volumes from further deterioration. Some of the procedures and techniques are just common sense control and prevention measures. Others might involve more careful attention to various environmental conditions and structural actions. 


Typically books are stored on shelves of various types. Metal and wood are common bookcase materials, but glass and man-made products are also used. Decor is one reason for choosing one shelving material over another. The cost of shelving can add up in a hurry too. 

If you choose wood bookshelves, be sure to use shelf liner paper which is acid free to protect the books. Wood can give off gasses which leave acid residue on your prized volumes, over time. Powder-coated metal shelves have the advantage of being acid free and sturdy enough to hold the weight of as many books as you place on them. 

When placing books on the shelves, place similar sized books together so they will help to support each other. They should be close enough that they provide spine edge support, but not so tightly packed that they are difficult to remove from the shelf without damage to the binding. Books which are too tall for the shelf can be placed flat on top of the bookcase, but should only be stacked three high. The books should be similar in size so they lay flat. 


Placement of your shelves is a key component of proper housing for your old books. Most archivists recommend placing your books on interior walls, rather than exterior walls. Exterior walls, no matter how well insulated, tend to experience temperature and humidity changes more readily than interior surfaces. 

Good airflow is another measure that helps to keep books in their best possible condition. Whether done by mechanical means in a single location, such as a fan, or by a whole house air conditioning system, books benefit from a well-placed system to circulate air regularly. 


Ultraviolet light as well as incandescent and fluorescent lighting can be quite damaging to books. Prolonged exposure to ultraviolet light is harmful to humans and books. Ultraviolet acts in the same way as bleach. Fading (sunning) damages both paper and leather in books. Keep your books out of direct sunlight to protect them from its harmful effects. All types of light sources are harmful, and exposure to both artificial and natural light can cause significant damage to delicate books and documents. Not only will inks and colors fade, but paper and binding materials will also deteriorate. LED lights are a preferable alternative to other types of artificial light.


The best way to keep insects out of your books is to make your library area unattractive to the egg-layers. If you notice an infestation, it is important to isolate the affected books immediately. There are various home remedies including freezing the books for several days inside a ziplock bag. For some types of insects, such as silverfish, using herbs like thyme or certain types of mint can be a repellent. The presence of essential oils such as lemon peel, celery, and mint, placed on the ends of shelves, can help to prevent silverfish from eating your copy of a childhood favorite.


A regular regimen of cleaning your book collection and the shelves on which they sit is a great way to eliminate some of the common contaminants which affect books, as well as giving you an opportunity to monitor areas and volumes where additional attention might be warranted. Each book should be removed from the shelf and wiped with a soft clean cloth, including the leading edges of pages. The shelf itself should be dusted before replacing the book. Shifting books around might prevent pressure marks. 

Temperature and relative humidity

Temperature control and relative humidity control are important for the care and condition of your books. Maintaining a fairly constant temperature between 68 and 72°F is best for the books. Relative humidity of 40 to 50% will be acceptable, as well. However, fluctuations of excessive amounts in either the temperature or relative humidity can be especially damaging to your books. 

Preservation of your books’ health and wellness

These tips and suggestions are intended for home library collections. More extreme suggestions are beyond the financial reach of many book lovers. Ideally, of course, a book which is never exposed to oxygen or light could be expected to last for a very long time. Expensive equipment and restoration procedures are typically reserved for only the most valuable items.