Alms Tax: Giving Mixed Items as Fitrah
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 2035
Wheat or any other thing that a person gives as fiṭrah must not be mixed with soil or any other thing. In the event that it is mixed and the item itself is equal to one ṣāʿ and it is usable without having to separate it from the other thing, or if separating it does not require extraordinary effort, or the amount that has been mixed is negligible, then there is no problem.
-Ayatullah Sistani, Practical Laws of Islam, Alms Tax (Zakat)