I say, and with God's guidance: There is doubt about its purification from the event (hadath), not about its purity, meaning that it is not judged to be pure or impure in relation to the event; it is doubtful regarding its purification from the event. If one does not find water other than it, he should perform ablution with it and then do tayammum (dry ablution), and whichever he performs first is permissible. However, it is permissible to remove real impurity from clothing and the body with it; because it is pure, and the doubt was only in its purification from the event. The reason for the doubt is the conflicting evidence regarding it, including: from Anas (may Allah be pleased with him): "The Prophet (peace be upon him) commanded a caller to announce: Indeed, Allah and His Messenger prohibit you from the flesh of domesticated donkeys, for it is impure, so the pots were overturned, while they were boiling with meat," in Sahih Muslim 3: 1539, and Sahih Ibn Hibban 12: 79, and Sharh Ma'ani Al-Athar 1: 205. This indicates the prohibition of the meat, thus the leftover (suur) is also impure; because its impurity and purity are considered based on the purity and impurity of saliva, and its impurity and purity are considered based on the meat. And from Ghalib bin Al-Ajr (may Allah be pleased with him), he said: "I asked the Messenger of Allah (peace be upon him) and said: There remains nothing of my wealth except for the donkeys. He said: Feed your family from your fat wealth, for I only disliked for you the roaming of the village," in Al-Mu'jam Al-Kabir 18: 266, and Sunan Abu Dawood 3: 256. This indicates the permissibility of its meat, which implies the purity of its saliva, which implies the purity of its leftover. And from Jabir (may Allah be pleased with him): "The Prophet (peace be upon him) was asked: Should we perform ablution with the water that the donkeys have drunk from? He said: Yes," in Sunan Al-Nasa'i Al-Kubra 1: 249, and Sunan Al-Daraqutni 1: 92. And from Ibn Umar (may Allah be pleased with him): "Do not perform ablution from the leftover of donkeys, nor from dogs, nor from cats," in Sharh Ma'ani Al-Athar 1: 20. Then it cannot be that the leftover of the donkey is impure by analogy with its milk; due to the great necessity for the leftover, and its scarcity in milk. Then it cannot be that the leftover of the donkey is pure by analogy with its sweat, for it is pure due to the great necessity for sweat, unlike the leftover. Then it cannot be that the leftover of the donkey is compared to the leftover of the dog and thus be impure, and to the leftover of the cat and thus be pure; due to the difference in terms of the necessity and its scarcity. See: Al-Talweeh 'ala Al-Tafweeh 2: 210, and Maraqi Al-Falah p. 28, and Nafi' Al-Mufti wa Al-Sa'il p. 26, and Kanz Al-Daqaiq p. 5, and Allah knows best.