Purchased from other players or on Grand Exchange.
Empty (right-click option) a Juju vial of water.
After drinking a potion made with the Juju vial of water you will be left with a Juju vial.
Uses:
When filled with water, used to make Herblore Habitat potions.
Notes:
You can fill Juju vials at Papa Mambo's cauldron outside his tent or any water sourced used to fill regular water vials.