Historical clue formulations

• "Later" — 2026-01-07
• "Toodle-oo!" — 2025-04-09
• "Peace" — 2024-09-05
• "Bye!" — 2024-01-25
• "Bye!" — 2023-12-14
• "Later!" — 2020-09-16
• "Bye for now" — 2015-06-07
• "So long!" — 2012-01-31
• "Later!" — 2011-11-30
• "Ta-ta!" — 2009-04-30
• "Ta-ta!" — 2006-08-15
• "Later" — 2005-10-13
• "Later" — 2005-05-25
• With 27-Across, holiday celebrators' farewell — 2001-03-09