a <#stamp> or <#stampenv=stamped envelope> that is no longer valid for postage. Those issued prior to the Civil War have been demonetized. Most pre-1979 <#postalcard=postal cards> have been effectively demonetized because they do not meet current minimum size requirements. Likewise <#sd=Special Delivery stamps> and <#newspaper=Newspaper and Periodical stamps> have been effectively demonetized.