The cleaning of wood furniture is sometimes required when, after dusting or buffing, the finish looks dull or heavily soiled, or if there is a build up of wax. Cleaning should be performed only as needed, not on a routine schedule. It should be attempted only on surfaces that have a sound, stable, clear tinish or on those that are completely unfinished. Cleaning should always be preceded by the removal of loose surface soil or dust. This can be accomplished by using a clean soft cotton cloth or a vacuum with clean soft brush attachment. The cleaning of historic wood furniture beyond dusting is not always desirable, and curatorial judgment is often required. Some furniture has developed a surface patina, accumulations of finish, wax, and soil that may in some cases be considered an integral part of the piece’s appearance. Wear and soil patterns can indicate historic uses and contribute to the unique value and character of the piece. If questions such as these arise, consult the Regional Curator or a conservator who specializes in furniture treatment for professional assistance.
Clear-finished furniture (those with a coating of shellac, varnish, or lacquer) can be cleaned only if the surface of the finish is neither embrittled, cracked, raised, nor flaking. To test the solubility of a finish, apply mineral spirits with a cotton swab to a small, inconspicuous area. Ifthe mineral spirits softens the finish, do not attempt to clean the piece. Consult the Regional Curator or a furniture conservator for professional assistance. After testing the finish, wipe the surface with a cotton cloth dampened with mineral spirits. A soft bristle brush dipped in mineral spirits can be helpful in cleaning hard-to-reach places around carvings and intricate decorations. Wipe the surface with a clean cloth and let dry for several hours. If a second cleaning is required to remove stubborn dirt, try wiping lightly with a clean cotton cloth dampened in a weak solution of a mild soap and warm water, and wrung out well. Follow this by a thorough wiping with a cloth dampened slightly in clear water and then dry completely with another clean cotton cloth. Never use detergents because they leave a tilm that is difficult to remove and which may permanently damage some finishes. Water should be used very sparingly when cleaning veneered or inlaid furniture. Clean one small area at a time, then wipe dry with a clean cloth before moving to the next area. If the finish is worn or cracked, use mineral spirits rather than water. Take care to avoid snagging the raised edges sometimes found on veneered and inlaid surfaces. The above cleaning methods will remove the protective wax coating, so rewax when the wood has dried completely.
Although rare in park collections, some furniture was traditionally finished with a coat of wax over the bare wood. Beyond dusting, no attempt should be made by park staff to clean such furniture because the methods described will damage this type of finish.
Because of the fragility or water solubility of some painted surfaces, it is recommended that they not be cleaned by park staff unless the staff is trained in distinguishing paint types and characteristics. Consult a furniture conservator regarding any treatment of painted surfaces beyond dusting.
Remove loose soil with a dry cloth or vacuum and brush attachment. It is recommended that park staff not use water to clean unfinished furniture because of the possibility of raising the
wood grain. If a piece is heavily soiled, it often can be cleaned using mineral spirits. This should be done only by trained staff or under the direction of a conservator.