Is it necessary to wash the part of the Mus'haf page that has been touched by saliva if a person touches it while having saliva on his hand?

If someone touches a mus'haf (copy of the Qur’an) with a hand that has saliva on it, it is obligatory to immediately wash the spot on the mus'haf’s pages that was affected by the saliva. There is no concession for this, and intentionally leaving it unwashed constitutes apostasy.