Related Clues:

• Sour - type of rain or drop
• Sour - LSD
• Corrosive substance
• Sour (substance)
• Sarcastic (could be sulphuric?)
• Sour — vitriolic
• Sour — sharp
• Amino or citric
• Chemical in drain cleaners
• Caustic drain unclogger
• Kind of wit in current papers
• Caustic stuff in Drano
• Something helpful containing cold, so-called drug
• Lawn liming target
• Caustic chemical used in making soap