What is the ruling on ill-gotten wealth that has become mixed with lawful wealth, and how can one dispose of it? What are the implications of this concerning livelihood, marriage, purchasing property, and debts? Is it permissible for the sinner to retain a portion of it out of necessity?

Public funds must be spent on the general welfare of Muslims. They can be spent on the poor and the needy. This includes what has been given to the poor, or to help the needy marry, or to support their families if no other source of income is available. As for what has been wasted on things other than those permissible by Sharia (definition), it must be disposed of with the intention of giving it away when possible. It is permissible to spend from it on oneself and one's family to the extent of need. It is also permissible to spend it on medical treatment or education if necessary.