Historical clue formulations

• Outdated postal abbr. — 2019-10-17
• Old postal letters — 2018-10-30
• Old letters in the mail — 2016-09-03
• Mail letters, in the past — 2011-04-01
• "Mayberry ___" — 2011-03-06
• Old postal abbr. — 2009-09-12
• Remote mail service: Abbr. — 2008-12-10
• "Mayberry ___" — 2007-08-26
• "Mayberry ___" — 2006-08-23
• Country rte. — 2006-04-19
• TV's "Mayberry ___" — 2004-05-31
• Mail abbr. — 2000-09-13
• Backwoods address abbr. — 2000-06-03
• Postal abbr. — 1999-01-23
• Mail letters — 1998-06-20
• Abbr. on a Mayberry envelope — 1998-02-01
• Letter letters — 1998-01-21
• Obsolescent mail abbr. — 1998-01-15
• Mail abbr. — 1997-06-27
• Mail abbr. — 1997-06-15
• Part of a Mayberry address — 1995-12-10
• Postal service, once: Abbr. — 1995-10-15
• Country mailing addr. — 1995-03-26
• Mayberry address — 1994-11-02
• "Mayberry_____" — 1994-10-27
• Postal abbr. — 1994-09-01
• Address abbr. — 1994-06-09
• Postal letters — 1994-04-05