Historical clue formulations

• Baseball cards, campaign buttons and such — 2017-11-25
• Diners and drive-in theaters — 2015-09-25
• Smithsonian artifacts — 2014-05-11
• Norman Rockwell specialty — 2008-06-27
• Some cultural artifacts — 2001-01-15
• Old United States maps, e.g. — 2000-08-26
• Things of national interest — 1998-07-03
• Smithsonian specialty — 1997-09-12
• Popular collectibles — 1997-01-31
• Britannica alternative — 1996-12-06
• Uncle Sam's stuff — 1996-05-03
• World Book rival — 1996-01-06
• Slice of _____ — 1995-11-25