Sayyed Muhammad Husaini Ragheb, Sayyed Muhammad Husaini Ragheb has a BA in Law from Guilan University, Iran and has also undertaken Hawzah studies in Qom. He used to be a Cultural Affairs director of Ethics Group of Al-Mustafa... Answered 2 years ago
Assalamu Alaikum
Let's bear in mind that IN PRAYERS for the Sajda(prosteration) to be done correctly, only the place that you put your forehead must be Taahir(pak or not Najis) which is the Turba and even if the mat is Najis but not wet then it's ok to pray on it.
Also in other than PRAYER:
Basically according to Sayyed Sistani (may Allah prolong his life) if the non-Muslim is Ahlul Kitab then you don't need to wash the mat because it has not become Najis.
but if they are non-Kitabi which means they are neither Christian nor Jew nor Zoroastrian, then according to obligatory precaution you must wash the mat to avoid the Nijasah reaching your clothes if it becomes wet.