What is the ruling on disposing of small amounts of unlawful wealth mixed with lawful wealth?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
When a small amount of unlawful wealth is mixed with lawful wealth, such as three Dirhams of unlawful money among a total amount, the obligation is to give away only the amount deemed unlawful in that small instance. If the unlawful portion is small, one should give it away entirely. This is based on the principle that the prohibition was due to the attachment of another person's right, and removing that right via restitution cancels the prohibition, making the remainder permissible. Imam Ahmad stated that if one has two hundred Dirhams with ten unlawful ones, one should give away the ten, as this is a large amount, whereas three unlawful Dirhams should be given away if that is all one possesses.
Supporting text
Sufyan stated that anything less than ten [units] should be given away, and anything more should be subject to further calculation. Al-Qadi stated that this is not a strict limit but rather based on preference (ikhtiyar). When the lawful portion is large, it becomes difficult to avoid all the unlawful portion, making it easier to only give away the minimum required, unlike a small amount where avoiding all of it is simple. The duty is to give away the certain measure of the unlawful amount; the remainder is permissible. However, piety (wara') dictates giving away everything to ensure the actual unlawful item is removed, but this is waived in large amounts due to hardship, thus limiting the action to the obligatory measure.