Historical clue formulations

• Source of smoke for a model volcano — 2025-04-09
• Shipping coolant — 2017-03-26
• Frozen CO2, familiarly — 2017-02-21
• Picnic cooler — 2009-05-29
• It sublimes at -109.26°F — 2000-08-25
• Common refrigerant — 2000-03-12