And from him, from al-Nadr, from Abdullah ibn Sinan, from Abu Abdillah عليه السلام, peace be upon him, who said:
I asked Him عليه السلام about praying in churches (biya’), synagogues (kanaʾis), and Zoroastrian fire temples (buyut al-majus). Imam عليه السلام said: "Sprinkle (them with water), and then pray."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 237