Possible Clues:

• Ingredient in some cakes
• Strongly alkaline wash
• Caustic stuff in Drano
• Cleaner's resting place reported
• Granny Clampett's soap ingredient
• Caustic drain unclogger
• After half a century one might leach with this from the Ashes (3)
• Common name for sodium hydroxide
• Industrial-strength cleaner
• Hominy-making solution