EXTREMELY FINE. THIS IS THE ONLY RECORDED EXAMPLE OF THE "OLD STAMPS NOT RECOGNIZED" HANDSTAMP ON A COVER WITH AN 1851 ISSUE IMPERFORATE STAMP--ALSO A LATE ATTEMPTED USE MORE THAN TWO YEARS AFTER DEMONETIZATION. A SPECTACULAR AND RARE CONFLUENCE OF THE ANTEBELLUM 1851 ISSUE AND THE CIVIL WAR.
After the U.S. Post Office Department declared its demonetization policy for stamps issued prior to the new 1861 Issue, federal post offices throughout the country were instructed to set expiration dates for the exchange of old for new issues--generally, the exchange period was six days from the date of receipt of new stamps. In Philadelphia the cut-off date was August 26, 1861, from which time letters bearing demonetized stamps were marked "Old Stamps Not Recognized". The Philadelphia "Old Stamps" marking and similar ones applied to mail originating in the North are related in purpose to the "Southern Letter Unpaid" handstamp, which was applied at the Louisville terminal office on mail originating in the South before all mail exchange was suspended. Examples with this marking on stamped covers are invariably found with the 1857-60 Perforated Issue. This is the only recorded cover with an imperforate 1851 Issue stamp and is one of the great rarities of the 3c 1851 Issue.
With 2013 P.F. certificate