Historical clue formulations

• Save for later — 2018-04-06
• Held in reserve — 2017-03-12
• Kept for later — 2016-12-25
• Reserve for future use — 2010-11-06
• Held in reserve — 2010-08-15
• Kept for future use — 2010-04-11
• Save for the future — 2010-01-10
• Put aside — 2009-07-17
• Save for future use — 1999-08-20