Historical clue formulations

• Base that dissolves in water — 2025-06-30
• Corrosive substance — 2021-11-22
• Acid's opposite — 2021-03-10
• Lye, for one — 2020-01-31
• High-pH compound — 2019-10-30
• High-pH substance — 2017-05-09
• Basic material — 2016-05-22
• ___ metals (periodic table group) — 2015-11-09
• Basic thing — 2014-11-07
• Base — 2013-11-10
• Lye, for one — 2012-05-18
• Soluble salt mixture — 2011-07-18
• Basic stuff — 2009-01-18
• Lye, e.g. — 2008-05-14
• Acid-neutralizing compound — 2003-05-13
• Acid neutralizer — 2003-04-27
• Potassium hydroxide is one — 2002-05-09
• Acid neutralizer — 2002-01-20
• Soluble mineral salt — 2001-12-23
• Acid neutralizer — 2001-06-28
• Acid neutralizer — 2000-09-17
• Acid neutralizer — 2000-02-29
• Poor soil ingredient — 1999-08-08
• Acid neutralizer — 1997-09-29
• Base — 1996-01-21