substanceCaustic AcidColors & materialsA named craft material / finish lemma (Caustic Acid) drawn as an exact public-domain workshop phrase.Caustic Acid is historically related to Salt.soap-manufacture seats orphan caustic-acid beside salt as a first craft peer — object speech, not a text-container or tradition dump.from W. H. Simmons & H. A. Appleton · The Handbook of Soap Manufacture, PD Gutenberg #21724historically related to · sourced · documentedsourcesThe Handbook of Soap Manufacture · W. H. Simmons & H. A. AppletonSimmons & Appleton, The Handbook of Soap Manufacture (PD Gutenberg ed.).