Is it permissible to pay out of one's monthly salary the same amount as the forbidden interest, as a form of seeking forgiveness?

Saving money for investment is permissible if it is done through Islamic institutions that adhere to Sharia regulations and invest in permissible areas. However, saving it in usurious institutions or companies that invest in prohibited activities is forbidden, and its returns are unlawful and must be disposed of by spending them on the welfare of Muslims or giving them to the poor and needy.

Whoever invests their money in forbidden institutions must repent by ceasing the act, feeling remorse, and resolving not to return to it. Their responsibility is discharged by expelling whatever they spent on themselves from the unlawful returns.

Ibn Taymiyyah said: "If money obtained through unlawful means is mixed with lawful money, then what is obligatory is to remove the unlawful portion, and the remainder remains lawful." Ibn al-Arabi said: "If the unlawful becomes mixed with the lawful, then investigation is obligatory to remove the unlawful so that the lawful remains pure." It is stated in "Al-Ikhtiyar": "Unlawful money may be disposed of. If it is spent on one's own needs, it is permissible. If one is rich, he should give a similar amount in charity. If one is poor, he does not need to give charity."