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Frequently Asked Preservation Questions


The following are some of the more frequent inquiries posed to NEDCC’s Preservation Specialists. The answers provide basic information, but it is important to remember that every situation is different. It is always best to contact a preservation professional for further advice.

How can I remove the musty smell from old books?

A musty smell is often noted in books that have been exposed to high relative humidity and that may have been moldy or mildewed in the past. There is no guaranteed way to remove the odor, but there are several strategies that may be successful.

One strategy involves creating an enclosed chamber. This is most easily done by using two plastic garbage cans, one large (with a lid) and one small. An odor-absorbing material, such as baking soda, charcoal briquettes (without lighter fluid), unscented clay kitty litter, or zeolites, should be placed in the bottom of the larger can. The object to be “deodorized” should be placed in the smaller can, which is then placed inside the larger can. The lid should then be placed on the larger can, and the chamber should be left for some time. Monitor the material periodically, since the time required to reduce the odors will vary from object to object.

A second option is the use of MicroChamber® paper, which contains zeolite molecular traps. These papers have proven very effective in removing odors. Place a sheet of the lightweight, 100% cotton interleaving tissue between the front board and the endpaper, then at every 20-50 pages depending on the size and condition of the volume, and finally between the back board and endpaper. Close the book and set it aside until the odor is reduced. It may be necessary to replace interleaving several times, putting new sheets at different locations in the book. For product information and supplies contact Conservation Resources at (800) 634-6932.

Our basement flooded and the pages of my high school yearbook are stuck together — what can I do?

Unfortunately, there may be little to do. Most yearbooks are printed on glossy coated paper. This is the same paper used in many art books. When coated paper gets wet and then begins to dry, the coating on facing pages sticks together and, once this occurs, it generally cannot be reversed. Freezing within about six hours, followed by vacuum freeze drying, can be successful in saving this type of material. Vacuum freeze drying should be carried out by a commercial service and can be relatively expensive.

Often, the pages are only partially stuck together. If this is the case, try to gently separate the pages with a Teflon folder (a bookbinding tool) or microspatula. Both are available from conservation suppliers. There will be some loss in areas where the pages were stuck, but some areas with information may be salvageable.

Another option is to purchase or borrow a copy of the yearbook and have a good-quality photocopy made. The photocopy could then be bound by a library binder. A good place to check for yearbook copies is the public library. Some maintain collections of local school annuals.

Finally, a conservator can provide an evaluation. The conservator may or may not be able to improve the object’s condition. If treatment is feasible it will likely be time-consuming and expensive, making this option most viable for items with high monetary or sentimental value.

How should I store my family photographs and papers?

Family photographs and papers should be protected from excessive heat, humidity and pollution. Attics and basements are generally not adequate as storage areas because of the tendency towards wide fluctuations in heat and humidity. It is better to store family collections in the main part of the house where temperature and relative humidity tend to be relatively stable.

Photographs and papers should be protected from light. Color photographs are especially vulnerable to deterioration. Exhibited items should not be placed in direct sun or in bright areas, and it is best not to exhibit any particular photograph or document permanently.

Important materials that will be kept over the long term should be stored in archival-quality enclosures. For papers, this usually means acid-free, lignin-free, buffered folders and boxes. For photographs, stable polyester enclosures (often sold under the trade name Melinex) are usually best. Conservation suppliers offer both polyester pages with pockets for photos and polyester and paper photo corners that can be used to mount photos on pH-neutral album pages. Photograph enclosures should also pass the Photographic Activity Test. Never use polyvinyl chloride (PVC) plastic pages or “magnetic” photo albums. PVC degrades rapidly and produces gasses that are harmful to photographs and papers, and the adhesive that holds photos in place in magnetic albums can also be very damaging.

Newsprint paper is of extremely poor quality and will continue to deteriorate even if it is deacidified or washed. Some inks are soluble in commercially available deacidification sprays, and some colors may change when they are alkalized. If a clipping is retained solely for informational purposes, the most efficient preservation strategy is to make a photocopy on archival-quality paper.

My books have an insect infestation— what should I do?

These may be booklice (also known as psocids) or silverfish. Booklice are extremely small (about 1–2 mm long) while silverfish are larger (up to 12.5 mm). The presence of silverfish and psocids often indicates a humidity problem in a storage area. Over time, silverfish can eat holes in paper collections.

If booklice or silverfish are noted, the first step should be to inspect collections to determine whether the problem is widespread or isolated. If only a few insects are seen, try to address the problem by reducing the humidity in the space and isolating and vacuuming the affected materials. Monitor the area for additional insect activity with sticky traps available from local hardware stores and other suppliers. If these measures are not successful, or if the problem is widespread, additional action may be necessary. Non-chemical measures are preferable to chemical treatments. It is best to contact a preservation professional to discuss appropriate options.

We have some old wooden bookcases in our library — how can we treat them to make them safe for our historical collection?

Many libraries have built-in wooden shelving for storing historical collections. From the perspective of preservation, it is best to store collections on metal shelving, since wood shelving can give off damaging pollutants. If wood shelving must be used, several steps can be taken to minimize damage to collections; however, none of these actions will provide complete protection.

All wooden shelving should be sealed; currently the best choice for sealant is a low volatile organic compound (VOC) moisture-borne polyurethane. Oil-based paints and stains should be avoided. Prior to application, it is important to make note of the required curing time for the paint or varnish used.

For further protection, shelves can be lined with museum board, polyester film, glass, Plexiglas, or an inert metallic laminate material (often sold under the trade name MarvelSeal) to prevent materials from coming into direct contact with the wood. Of the lining options, MarvelSeal is the only one that provides a true vapor barrier, but it can be less aesthetically appealing and more difficult to use than some of the alternatives.

If collections will be stored in closed wooden cabinets or shelving, the cabinets should be aired out several times a year to minimize buildup of damaging fumes.

I have some old leather books with dried and cracked bindings — should I put leather dressing on them?

The use of leather dressings (neatsfoot oil, lanolin, etc.) was widespread in libraries for many years, but the conservation community now recommends that it be avoided in most cases. Research and experience have shown that leather dressings can have some undesirable side effects, including discoloration, staining, and stickiness of the leather, wicking of oil into adjoining materials including text blocks, and increased danger of mold growth on treated materials. Leather dressing may be appropriate for some objects, but should be used very sparingly and advice should be sought from a conservator before use.