Never use pressure-sensitive adhesive tapes to repair tears. The tapes will provide a short term answer but over time will create worse problems, such as irreversible disfigurement, embrittlement of the paper, and alteration of inks. Tapes marketed as “archival” may still contain unsafe materials.

Pure wheat-starch paste, or methyl cellulose and Japanese tissues, provide the best answer for mending tears, but both are water-based and can be tricky to work with on clay-coated papers. To preserve the condition and value of a rare issue, repairs such as flattening, mending of tears, and filling of losses are best done by trained paper conservators.