Historical clue formulations

• Sugar in one's coffee, e.g. — 2021-12-17
• Something that disappears in a chemistry experiment — 2021-05-04
• Substance in a chemistry experiment — 2010-12-16
• Sugar in tea, e.g. — 2008-08-17
• Sugar in coffee, e.g. — 2005-08-07
• Dissolved substance — 1995-05-14