Prayer: Using a Blackened, Dirty Turbah for Sujūd: Is It Problematic?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: Using a Blackened, Dirty Turbah for Sujūd: Is It Problematic?

English:

Question #489:

Is there any problem in using, for prostration, a turbah blackened and dirty in such a way that the stain covering it obstructs the forehead from touching the turbah?

Answer #489:

If the stain on it is so much as to form a barrier between the forehead and the turbah, the prostration is void and so is the prayer.

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer