Historical clue formulations

• Ingredient in some hair relaxers — 2026-09-20
• Aid in making soap — 2026-08-03
• Caustic paint stripper — 2026-03-30
• Caustic cleaner — 2026-03-04
• NaOH — 2025-12-18
• Harsh cleaning agent — 2025-11-10
• Common name for NaOH — 2025-06-10
• Caustic drain cleaner — 2025-01-13
• "That's a ___!" (chemist's punny observation) — 2024-10-20
• Substance in a bagel-making "bath" — 2024-07-28
• Caustic cleaner — 2024-07-18
• Solution for many cleaning problems — 2024-06-29
• Caustic solution — 2024-05-14
• Wood ash + water — 2024-05-10
• Very basic stuff? — 2024-05-07
• Soapmaking ingredient — 2023-09-12
• Caustic cleaner — 2023-09-10
• Strong cleaner — 2023-02-01
• Compound used to make soft pretzels — 2022-11-18
• Caustic agent — 2022-08-02
• Ingredient in soapmaking — 2022-07-18
• Pipe cleaner — 2022-04-15
• It may be part of a solution — 2022-03-20
• NaOH, familiarly — 2021-10-12
• ___ soap — 2021-09-26
• Harsh cleaning agent — 2021-05-25
• Cleaning solution — 2021-05-09
• Caustic solution — 2021-04-05
• NaOH — 2021-03-07
• It's used in soapmaking — 2021-02-10
• Basic cleaner — 2021-01-29
• Strong base — 2020-10-22
• Corrosive cleaner — 2020-09-28
• Homophone of 24-Across — 2020-06-01
• Basic cleaner — 2020-05-01
• Drano component — 2020-03-29
• Chemical compound with the formula NaOH — 2019-01-28
• Ingredient in a drain declogger — 2018-11-14
• ___ soap — 2018-09-18
• Soapmaker's supply — 2018-08-01
• Powerful cleaner — 2018-05-28
• Burn cause — 2018-02-08
• NaOH — 2017-10-28
• Caustic soda — 2017-10-15
• Chemical in Drano — 2017-06-28
• Caustic agent — 2017-01-02
• Strong base — 2016-01-15
• Corrosive stuff — 2016-01-13
• Oven cleaner ingredient — 2016-01-10
• Caustic substance — 2015-05-13