What is the ruling on taking money from a prostitute, and is it obligatory to return it, and what are forbidden earnings?

If all of a woman's money comes from zina (fornication/adultery), then it is not permissible to deal with her or accept anything from it. However, if her money is mixed between lawful (halal) and unlawful (haram) sources, then eating from it is not forbidden, but it is disliked (makrooh), and the degree of dislike increases with the proportion of the unlawful. It is preferable to refrain entirely from taking any of her money to deter her. If money that is unlawful to take is received from her, then it is obligatory to give it as charity to the poor and needy.