Related Clues:

• Soapmaking caustic
• Sulphuric, for one
• It has a pH below 7
• Rock type
• Caustic cleansing agent
• Chemical in Drano
• Sulfuric substance
• It was dropped at Woodstock
• Trip provider?
• Caustic soapmaking compound
• Base's counterpart
• Chemical used to make biodiesel
• Drano ingredient
• Digestive fluid
• Folic ___