Is it permissible to pay off a wife's debt with money acquired from usury, with the intention of getting rid of that money?

The questioner must repent from dealing with usury and dispose of any amount exceeding his principal by returning it to its owners if he knows them. As for paying his wife's debt, it is permissible if it is from his principal capital. However, if it is from usurious money: it is not permissible to pay her obligatory maintenance debt, because it is a debt specific to him, and he is not permitted to benefit from it. But if her debt is for other matters unrelated to obligatory maintenance, then there is no objection to paying it from the usurious money with the intention of getting rid of it, if she is unable to pay it herself.