Historical clue formulations

• Hardened (to) — 2013-04-24
• Hardened — 2011-09-27
• Accustomed — 2008-01-28
• Hardened — 2007-06-30
• Accustomed — 1999-01-18
• Hardened — 1997-10-19
• Toughened — 1995-04-30
• Hardened — 1994-11-14
• Habituated — 1994-08-27