Related Clues:

• Tart-tasting
• Aspirin, e.g.
• Oven-cleaning chemical
• Citric ___
• Test subject
• Word with indigestion or test
• Caustic agent
• Sour-tasting
• Soapmaking need
• Soap-making ingredient
• Battery fill
• High-pH stuff
• Hydrochloric, for one
• Basic cleaner
• Litmus-reddening substance