1. "Canonically impure property" is a kind of property that is prohibited from being used and owned according to sharia.
2. No matter how much time has passed, a person who, for some reason, took possession of dirty property is not considered the real owner of the same property. If that person recognises the real owner of the property, it is considered a bounden duty for him to return it to the real owner or to his successors. If he has lost hope of finding the owner, he will have to spend on charity in order to get rid of it. At the same time he makes donations on behalf of the owner of the property.
3. If one receives a dirty property as a reward for any dirty job, he also spends the property for charitable purposes. He doesn't give it back to the person who gave it.
4. If a person has a dirty property received not according to sharia, he, like the benefit of usury, does not return it to the owner, and spends on charity.
5. If it is impossible to return that a dirty property, he must return it to the owner its analog or value. If he does not recognise the owner, he also spends it on charity, intending to donate on behalf of the owner.
6. A dirty property does not replace zakat, that is not considered the property for which zakat is given, as from the point of view of sharia, such a property has no value. Such a property acquired in a dirty way must be disposed of in the way specified in the sharia.
7. If someone takes possession of someone else's property against sharia law, he is not allowed to give zakat from that dirty property because there is no absolute ownership of that property, which makes it mandatory. When the property is returned to its owner, it is necessary to give zakat for the year of receipt, even if several years have passed.
8. If someone who takes possession of an unclean property, gives zakat from that property without returning it to his real owner, he will still be considered sinful for the rest of the property. And the part that was released is considered the release of the part that was to be returned according to sharia, and will not be considered as zakat. And also it does not save him from responsibility. He must return it to the owner only if he recognises him, and if not, he must make a donation on his behalf.

Sheikh Muhammad Sadik Muhammad Yusuf

(From the book "Salvation of the muslim")