Historical clue formulations

• Prefix for element #8 — 2026-01-20
• Lead-in to -tocin — 2024-12-03
• Big name in acne medication — 2022-08-10
• Competitor of Stridex — 2022-06-25
• Popular acne medication — 2021-11-22
• Houston-based petroleum giant, informally — 2018-09-23
• Acne medication brand — 2018-01-04
• Sister brand of Phisoderm — 2015-11-29
• California school attended by Obama, familiarly — 2015-08-23
• Clearasil rival — 2013-12-16
• Moronic beginning? — 2011-12-10
• ___-10 (acne medication) — 2010-06-20
• Acne treatment brand — 2007-01-10
• Prefix with acetylene — 2005-07-27
• Prefix with acetylene — 2005-04-25
• Prefix with acetylene — 2002-12-16
• Prefix with tetracycline — 2002-04-19
• Big oil company, for short — 2001-01-07
• Prefix with acetylene — 2000-11-07
• Nickname in the oil biz — 2000-05-01
• ___-10 (acne-fighting medicine) — 2000-03-29
• Big oil company, informally — 2000-01-28
• Petroleum company, informally — 1994-11-28
• Acetylene starter — 1994-06-10