How to Care for Old and Rare Books: A Preservation Guide

Old books are more durable than they look. A well-made book from the eighteenth century, properly stored, can remain in fine condition indefinitely — the paper still white, the binding still tight, the text still perfectly readable. The enemies of books are specific and, for the most part, avoidable: light, moisture, heat, pests, poor storage, and careless handling. Control these and your books will outlast you.

Light: The Silent Fader

Ultraviolet light is the primary cause of fading in cloth and leather spines, and of the yellowing and browning of paper. Direct sunlight is the worst offender, but fluorescent lighting also emits UV in significant amounts. Books displayed in sunny windows or under unshielded fluorescent light will fade visibly within a few years.

Solutions are simple: keep valuable books away from direct sunlight, use UV-filtering window film in rooms where books are shelved, or choose UV-filtering bulbs. The simplest approach — bookshelves in darker areas of a room, or books stored in closed cases — is also the most effective.

Temperature and Humidity

Books thrive in cool, stable conditions: around 60–65°F (15–18°C) and 30–50% relative humidity. High humidity encourages mold and causes wooden boards and vellum bindings to warp; low humidity dries out leather and makes paper brittle. Basements tend to be too damp; attics too hot and variable.

Stability matters as much as the specific values. Frequent swings between warm and cool, dry and humid, cause more damage than a consistently imperfect environment, because they cause the book's materials to expand and contract repeatedly. A climate-controlled living space is adequate for most books. Truly rare or valuable volumes may warrant purpose-built climate-controlled storage.

Shelving and Support

Books should stand upright on shelves, supported so they do not lean. A book that leans for years accumulates stress in its spine and binding that manifests as permanent distortion. Use bookends; they do not need to be elaborate, only stable and smooth-surfaced enough not to damage adjacent covers.

Very large books — quartos and folios — do better lying flat, as their weight can crack spines over time if they stand vertically. Stack them horizontally in groups of no more than three or four, face up, with the heaviest on the bottom.

Do not pack shelves too tightly. You should be able to remove a book by grasping it at mid-spine and pulling gently — not by yanking it out by the headcap, which is the small projecting bit of the spine at the top. Pulling books out by the headcap is one of the commonest causes of spine damage, and the damage accumulates invisibly over years before becoming obvious.

Handling

Clean, dry hands are the single most important handling tool. The oils and acids on fingertips accelerate the deterioration of paper and leather; over years of regular handling, the margins of a frequently read book will discolor noticeably compared to the center of the page.

When opening an old book that has not been read recently, open it gently from both ends in small increments — a few pages from the front, a few from the back, working toward the center — rather than forcing it flat from the middle. This is especially important for tight-backed bindings and for books with dried-out leather covers, which can crack along the hinges if forced open.

Never place a book face-down, open, with the spine under tension. This breaks down the spine quickly and is one of the most common forms of avoidable damage.

Cleaning

Dust is the most common problem and the easiest to address. A soft natural-bristle brush — a good watercolor paintbrush or a dedicated book brush — is ideal for cleaning the edges of pages and the exterior of covers. Hold the book closed while brushing the page edges, working from spine to fore-edge, to avoid driving dust into the gutter.

Leather bindings benefit from periodic conditioning. The best material for most bookbinding leathers is a microcrystalline wax (Renaissance Wax is widely used by conservators). Avoid shoe polish, mink oil, and general leather conditioners — many contain chemicals that damage bookbinding leathers over time, and some leave sticky residues that attract more dust.

Be very conservative about cleaning paper. Most eraser types are abrasive enough to damage aged paper, and many stains that seem improvable are not. Surface dirt on pages can be lifted gently with a soft eraser crumb worked very lightly across the surface — but only if you know the paper is strong enough to take it. When in doubt, do nothing. An expert conservator can do far more safely than an amateur experimenter.

What Not to Do

A short list of common mistakes:

• Rubber bands — leave marks and degrade into a sticky residue over time
• Tape on paper — almost all pressure-sensitive tapes are nearly impossible to remove without damaging paper, and most discolor and fail within decades
• Plastic bags for storage — trap moisture and can cause condensation damage
• Stacking heavy objects on books — distorts bindings and boards
• Storage near radiators or heating vents — causes extreme drying and temperature fluctuation

If you discover active mold on a book — a powdery growth, often white or green — isolate it immediately from other books and do not attempt to clean it yourself. Mold spreads readily to neighboring volumes and the wrong cleaning technique can drive spores deeper into the paper. Consult a book conservator.

When to Call a Conservator

For books of significant value — monetary or sentimental — professional conservation is worth considering before attempting home repair. Book conservators can stabilize damaged bindings, clean pages with materials and techniques not available to amateurs, consolidate fragile leather, and advise on storage solutions for specific problems. They can also tell you when a book is better left alone than improved.

Browse our current inventory of antiquarian and used books. If you have questions about caring for a specific type of book, reach out — we are glad to help.