Was invalidating stamps considered under 1970 Postal Reorganization Act?

The Postal Reorganization Act of 1970 changed the name of the United States Post Office Department and more. But there were things it didn’t change — despite rumors to the contrary.

The Spectator, Sept. 1970 - May 1971 by Hamilton College - Issuu

Greetings! from Kimberly Shaw: My Two Cents

6 Stamps That Commemorated U.S. History

U.S. special delivery stamps used in Canal Zone

Read the Supreme Court Decision - The New York Times

Postage stamps and postal history of the United States - Wikipedia

Deutsche Post of the GDR - Wikipedia

Jan 1970 - On-Line Newspaper Archives of Ocean City - The Ocean

Anniversary of repeal of Stamp Act commemorated