The World Federation One Stop Fiqh

Ruling 148

If a pitcher that is made from impure clay, or a pitcher which impure water has permeated, is placed in kurr or flowing water, then 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 thereafter placed in kurr or flowing water.