Historical clue formulations

• Rust and quartz — 2020-09-06
• Lime and others — 2018-03-03
• Laughing gas and rust, for two — 2017-05-17
• Rust and lime — 2012-06-04
• Rust and quartz — 2011-12-29
• Laughing gas and water, chemically — 2008-04-20
• Rust and lime, for two — 2003-11-12
• Some binary compounds — 1997-09-24
• Waste gases, e.g. — 1997-05-14
• Lime and others — 1997-03-16
• Rust and others — 1995-05-05