What is the ruling on one who divorced his wife and did not give her delayed mahr, and does not know her whereabouts, and wishes to clear his conscience?

The deferred dower must be returned to the wife or her heirs. If she cannot be reached, her relatives or friends should be asked to help you reach her, requesting her forgiveness. If you search and do not find her, then give the money in charity on her behalf. Afterwards, if you learn of her whereabouts, give her the choice between ratifying the charity or taking her money. You must repent, seek forgiveness, regret what you have done, and increase in performing righteous deeds.