Purifying Doors and Windows with Running or Small Water — Jurisprudential Answers — Book of Purification

Ahmed al-Hasan Response:

If running water predominates over the impurity and its characteristics, the place becomes pure. Thus, an impure spot on a door, window, or similar object may be purified with running water by pouring running water over the impure place and rubbing it until it becomes pure. The runoff is pure if the running water has predominated over the impurity and its characteristics. To purify an impure spot on a door or window with a small quantity of water, take a sponge and immerse it in pure water until it is saturated, then wipe the impure place with it to remove the actual substance of the impurity. Wash the sponge, immerse it again in pure water, and wipe the place a second time. This final wiping is the purification washing, after which the place is pure.