Is it authentically reported from Ali and Ibn Mas'ud—may Allah be pleased with them both—that they held the view of the purity of the skin of a dead animal—except for the dog and the pig—through tanning, as related by An-Nawawi?

What has been narrated from Ibn Mas'ud concerning carrion is his saying: "Its purification is its tanning" and "Its tanning is its purification," and the narrators in its chain are trustworthy. No text from Ali ibn Abi Talib has been found regarding this matter.