What is the ruling and what must be done after discovering that the perfume used to scent the Mus'haf contains an unknown proportion of human urine? And is it obligatory to wash the copies of the Mus'haf that were scented with it?

The default state of things is purity, and nothing is judged to be impure except with certainty. If the matter is merely a doubt, then the perfume is pure, and it is permissible to perfume the Qur’an with it. However, if there is certainty that the perfume has mixed with urine, even a small amount, then it is considered impure, and it is forbidden to put it on the Qur’an in the future. The pages of the Qur’an on which the perfume was placed must be purified with ritually pure water.