Historical clue formulations

• The solution referred to in Sherlock Holmes's "seven-per-cent solution" — 2025-09-13
• Illegal import from Colombia — 2020-01-06
• Ingredient in a Brompton cocktail — 2015-08-08
• Drug from Colombia — 2010-11-01
• Ingredient of a speedball — 2005-06-12
• Some contraband — 2000-04-26
• Anesthetic, once — 1999-10-10