Muhammad, from Muhammad ibn Al-Husayn, from Safwan, from Jamil, from Al-Hasan ibn Shihab, said:
I asked Abu Abdillah عليه السلام, peace be upon him, about fox skins, if they have been purified (lawfully slaughtered), may one pray in them? Imam عليه السلام said: "Yes."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 395