Q. I have several 19th century leather bound books which I would like to preserve as best as possible, what would you suggest?
A.You may want to consult with a local conservator, AIC has a finder.
In general, it is important that the books be kept free of dust, insects and mold spores and that they be kept in a temperate area with relatively stable humidity in the mid-range. Aim for temperatures comfortable for you and humidity in the 40 to 60% range. Humidity above that encourages mold. Try to shelve on an interior wall, if possible. This avoids temperature swings possible along outside walls, which both stresses the leather, boards and paper and can cause condensation.
Periodic gentle vacuuming (cover the end of the tube with nylon) will accomplish the first. (If you know you are sensitive to mold, you of course will use a vac with HEPA filtration or seek the services of a professional conservator.) Soft-bristle brushes also work well. After vacuuming, dust regularly. Use Renaissance Wax or a natural vulcanized rubber sponge for cleaning. The sponge is wonderful for pages edges and inner boards. Do not be alarmed if the color lightens appreciably as years are cleaned away! Use a conditioner to feed the leather. When cleaning and treating be especially careful of gold leaf and other ornamentation. Cover pages with waxed paper or foil to protect them when working with the leather care materials.
Wooden bookshelves should either be sealed with an inert sealant or there should be a buffer layer of glass or other inert material beneath and behind the books. This will protect the books from the oils naturally present in the wood and and from polishes and wood treatments. Large and moderate-sized books should always be stored vertically with books of similar height for support and just a bit of ease for air circulation. Very small or thin books or pamplets may be shelved horizontally.
When storing or moving, use only nonbuffered packing materials. Buffered materials can interact with some leather dyes, causing a reaction that could alter color in some areas.