Is it sufficient to pour water over vaginal discharge contaminated with urine on the external vulva to purify it and for the woman to be considered properly cleansed, or must it be completely removed with water and rubbing?

Pouring water over the area contaminated with urine is sufficient to purify it. Certainty of the purity of the place after washing is not a prerequisite; rather, the predominance of conjecture is sufficient. As for a place where one doubts its contamination with urine, the original ruling is that it has not been affected by it, so washing it is not obligatory. One is warned against giving in to obsessive doubts.