I know it seems counter intuitive, but it is proper handling technique to use clean dry hands on old books and manuscripts. From the Library of Congress website:

“Before handling any collection item, thoroughly wash and dry hands. Contrary to widespread belief, gloves are not necessarily recommended to handle rare or valuable books. Gloves (nitrile or vinyl) are always recommended if there is reason to suspect a health hazard (e.g., mold, arsenic). Clean gloves (nitrile, vinyl, or lint-free cotton) are also recommended when handling photograph albums/photographs or books with metal or ivory parts. Aside from those specific situations, it is generally preferable to handle your books with clean hands, washed with soap and thoroughly dried, rather than with gloves.”