Related Clues:

• 91-Across, e.g.
• Etcher's purchase
• Low pH
• Sulfuric or hydrochloric follower
• Astringent in wine
• Type of rain
• Corrosive chemical
• See 48 Across
• Dropped stuff
• Car battery component
• Cause of some bellyaching
• Annoy no end
• Corrosive compound
• Low-pH liquid
• LSD or HCl