Historical clue formulations

• Device placed under a tongue — 2023-12-31
• Shape preserver, of a sort — 2011-10-29
• It's exactly a foot long — 2005-03-04
• Pump preserver — 2002-09-29
• Loafers don't grow on this — 2000-02-23
• Closet item — 1995-05-13