Purity: Purification of Pitchers and Utensils Made from or Contaminated by Impurity

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 148

If a pitcher made from impure clay, or a pitcher which impure water has permeated, is placed in kurr or flowing water, wherever the water reaches becomes pure. If a person wants its inside to become pure as well, it must stay in kurr or flowing water for such a length of time that the water permeates all of it. Furthermore, if a utensil has some liquid that prevents water from reaching its inside, it must be dried and placed in kurr or flowing water.

-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)