How can a Discman be returned to its unknown owner whose place of residence is unknown, and how can contact with bad companions be avoided? Is it permissible to sell it and donate its price?

The device must be returned to its owner, even if indirectly. It is not permissible to sell it and donate its price as long as it is possible to return it, due to the Prophet’s (peace and blessings be upon him) saying: “The hand is responsible for what it has taken until it returns it.” If it is impossible to know her whereabouts, it can be sold and its price donated on her behalf. When you meet her, she should be given the choice between affirming the charity or taking the price.