Miriam:

A standard archival rule of thumb for confidential material is to keep the
document closed for 75 years past the latest date on it.  After 75 years you
can be reasonably sure that the individual mentioned is dead, and the dead
have no right to privacy.  Check the book published by the Society of American
Archivists titled, Archives & Manuscripts: Law by Gary Peterson and Trudy
Huskamp Peterson for more details and all the legal vagaries.

Michael Knies
Collections Manager/Archivist
National Canal Museum
Easton, PA
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