Two sketchbooks by Paul Cézanne recently acquired by the Philadelphia Museum of Art have undergone conservation analysis and treatment. Approximately forty years ago, the sketchbooks were dismantled and the pages were adhered to mats with pressure-sensitive tape. Treatment has focused on removal of the oxidized tape stains. The carriers and brittle adhesive crust were pared down while being viewed through a stereomicroscope. Local exposure to solvent fumes was used to soften the adhesive prior to mechanical reduction. This was followed by local solvent application on a suction disk to reduce staining. The advanced state of adhesive oxidation, as well as the sensitivity of the paper to solvents, made stain removal extremely problematic. Many polar solvents solubilized the adhesive by caused tidelines or overcleaning of the paper. Methylene chloride most successfully solubilized and removed the adhesive on the suction disk. VM&P naphtha was used as a barrier solvent to diminish lateral spreading of methylene chloride. Local solvent treatment was monitored by ultraviolet light.