How should I dispose of a salary I received by mistake for an unpaid leave month, knowing that it cannot be returned to the company?

It is not permissible to take the salary for the second month when obtaining unpaid leave, unless authorized by the competent authority from the administration. In that case, it is permissible to take it, as it is considered a gift. However, if the one who authorized it is not competent, then it is not permissible to take the salary, and it must be returned to the employer. It can be returned in a way that does not harm the mistaken employee.