Related Clues:
- What red indicates in litmus tests
- It's been taken for many trips
- Caustic agent in soap
- Low-pH stuff
- Lutefisk-curing need
- Alkali balancer
- Lemon juice, e.g.
- Oven-cleaner ingredient
- It is neutralized by alkali
- __ rock
- A strong alkaline solution
- It turns litmus red
- Caustic and biting
- Substance which turns litmus red
- It's corrosive