Is it permissible to cleanse oneself with holy books if they have been distorted?

Scholars differed concerning the ruling on using corrupted scriptures, such as the Torah and the Gospel, for purification (Istinja’). The majority of scholars prohibited it due to the sanctity of the names of Allah or the letters themselves, absolutely. However, some Shafi‘is permitted it if one is certain that they are free from the names of Allah and whatever the Shariah has sanctified. This is because the sanctity of the letters remains even if what is written is falsehood, such as magic, or the altered Torah and Gospel. Thus, the prohibition is due to the letters or the names of Allah written therein.