Historical clue formulations

• Sidewalk writing medium — 2025-09-16
• White stuff on a blackboard — 2020-02-10
• ___ talk — 2019-08-21
• Snooker accessory — 2016-06-16
• Sidewalk writing aid — 2013-07-02
• Gymnastics school supply — 2010-07-17
• Lesson writer? — 2010-03-11
• Writer on a slate — 2007-05-21
• Pool accessory — 2004-06-18
• Hopscotch player's buy — 2003-06-25
• Like Dover's cliffs — 2003-04-13
• It's rubbed on a cue tip — 2003-02-10
• Pool hall need — 2001-12-12
• Poolroom need — 2001-04-03
• Billiards need — 2000-08-06
• Classroom supply — 1998-06-23