Historical clue formulations

• Words below the Lincoln Memorial — 2012-05-07
• Words below the Lincoln Memorial — 2007-04-03
• Minimal postage hike — 2005-11-24
• Minimal amount — 2005-03-11
• Bygone Tootsie Roll price — 2000-11-23
• Like old postcards — 2000-08-24
• Like early postcards — 1997-10-12
• Copper — 1996-01-26