Answered by Sidi Fadi Qutub Zada
Is the wetness of a cats nose, or the saliva of a cats mouth considered to be filth?
In the name of Allah, the most Compassionate and Merciful
Cat saliva is not considered filth because of the hadith that Abu Qatada (Allah be pleased with him) related, that the Messenger of Allah (Peace be upon him) said (about the cat):
“It is not impure, it is of those [creatures] that mingle with you.” [Reported by Tirmidhi, Abu Dawud, Nasa’i, and Ibn Maja]
It is mentioned in Hashiyat al-Tahtawi:
If a cat drinks from a container, however, or licks ones hand before praying, then it would be mildly disliked (makruh tanzihan) to drink from that same container, or to pray without washing off the traces of saliva from ones hand. This is if one suspects it to have eaten filth or is uncertain of its statewhether impure (from eating filth) or pure. If a cat eats a mouse and drinks water immediately after, then the water becomes impure. However, by licking its mouth for a short while, the mouth is purified and it is no longer impure. [Tahtawi 1:18, Dar al-Iman]
And Allah alone gives success.