Oil on Paper: A Collaborative Conservation Challenge

The application of oil-based leather dressing, while once considered a best practice in libraries, led to undesirable long-term consequences for bound materials. At the National Institutes of Health (NIH) in the National Library of Medicine (NLM), many leather-bound volumes had multiple applications of a mixture of neatsfoot oil and lanolin dressings liberally applied. The oils not only absorbed into the leather bindings but also migrated onto the pastedowns, end sheets, gutters, and text blocks. The oiling process at NLM was documented by call number, year(s), number of applications, and dressing formula. While investigating treatment options, the NLM senior conservator consulted a paintings and objects conservator for insight on viable options for the removal of oil from artifacts. An art-on-paper conservator joined the collaborative effort to develop a treatment protocol for NLM's oil saturated collections. Together, they investigated the issue and devised an effective method for removal of this oil from the NIH collection materials. The protocol involves washing with an alkaline solution followed by alternating applications of petroleum ether and acetone applied either over suction or by immersion. Oil components are solubilized by the alternating polarities of the solvents and then removed from the paper using suction or immersion. After the oil is removed, the paper is washed again with alkaline water to remove any remaining water soluble discoloration. This article will explore further details of the treatment protocol, its development and applications, and the benefits of cross-disciplinary collaboration.