Since Grimtooth is permanently poisoned, dipping it in an uncursed potion of water should turn it into a potion of sickness, and dipping it into a pool or moat should turn it into sewage.

Any corpse which has touched sewage is automatically tainted if you try to eat it.

You occasionally abuse Charisma when trudging through raw sewage.

When a pool of raw sewage boils away, it creates a poison gas cloud over that space.