Abdur Rahman bin Wa'lah said: I asked Sayyiduna Ibn Abbas (may Allah be pleased with them both) about a leather water-skin (in which water is filled), so he said: I do not understand what answer I should give you except that I heard the Messenger of Allah (peace and blessings be upon him) say: "Any hide that is tanned has become pure."
Hadith Referenceسنن دارمي / من كتاب الاضاحي / 2024
If the hide of an animal whose flesh is eaten is cleaned with salt, tree leaves, etc., it becomes pure, and it is permissible to benefit from it, even if the animal is dead, as will be mentioned in the following hadith.
In this hadith, «أَيُّمَاإِهَابٍ» is general, meaning that any hide which is tanned becomes pure. From this generality, the scholars have deduced that it applies to the hide of any animal.
Imam Abu Hanifah rahimahullah said regarding the hide of a pig, and Imam Shafi‘i rahimahullah said regarding the hide of a dog and a pig: it will not be permissible or pure in any circumstance.
Similarly, the hide of a human being will also not become pure or usable through tanning.
The pig and the dog are not permissible due to being impure and filthy, and the hide of a human being is not permissible to benefit from due to the human being’s honor and dignity.