What are the things accepted as clean in islam? What is considered clean in islam?
In Islam, the basic premise is that things are ritually pure unless demonstrated to be otherwise. The entire earth, inanimate substances, whether solid or liquid, grass, trees, flowers, fruits, human beings, whether living or deceased, and the outer sides of the bodies of all animals, except the pig, are accepted clean as a general principle provided that they have not been contaminated by some other substance which would render them impure.
The Ḥanafis holds that the only ritually impure animal is the pig, while according to the Malikis, no animal is intrinsically impure, therefore, dogs, pigs, and their offspring are all ritually pure. Whereas, according to the Shafiʿis and the Ḥanbalis, dogs, pigs, and their offspring, or the offspring of one of them having mated with something else, are considered impure.
According to the Ḥanafis, the fur and skin of a live dog and elephant are clean. The water that touches them is also considered clean. The skins, liver, heart, spleen, and blood not flowing but remaining in the meat of all of the animals after they have been slaughtered in accordance with the Islamic law are clean. Such is even the blood of small insects such as lice, fleas, and bed bugs. However, the pig does not become clean even when it is slaughtered in accordance with the rules of Islamic law.
According to all schools, fish and other animals that live and die in water are clean. However, according to the Ḥanafis, it is not permissible to eat the meat of animals that live and die in water other than fish.
According to the Ḥanafis, the parts of the animals, with the exception of the pig, into which blood does not penetrate do not become unclean in the event of the death of the animals. That is why the horns, nails, bones with no fat, clipped hairs, feathers, and tanned skins are considered clean. So are the hair, bone, and teeth of human beings.
According to the Ḥanafis the purity and impurity of a living being’s tears, sweat, saliva, phlegm, bile and sputum, and dirt, and their cleanliness are subject to the same ruling as the residual water of the living being in question. If its residue is clean, the above-mentioned liquids are also considered clean. The saliva of mules and donkeys is clean, the saliva of birds of prey and animals living in houses such as mice, snakes, scorpions, and cats is makrūḥ; The saliva and residues of pigs, dogs, and other wild animals are impure. Human saliva is clean. However, if he drinks alcohol, his leftovers and saliva are not considered clean unless he cleans his mouth.
The Maliki school holds that saliva, which is secreted by the mouth in both waking and sleeping states, is ritually pure; however, what comes back up from the stomach and returns to the mouth is impure; such impure substances may be recognized by the change in their color and odor, as they tend to be yellowish and foul-smelling. Whereas according to the Ḥanbalis, tears, sweat, saliva, and mucous are all ritually pure whether they come from an animal whose meat may be eaten or from some other animal, provided that the animal is similar to or smaller than a cat, and that it does not originate from impurity. Finally, according to the Shafiʿis, these things are ritually pure if they come from a ritually pure animal, whether its flesh may be eaten or not. They also hold that the venom of snakes and scorpions is ritually pure.
The excrements of birds whose meat is edible and defecate in the air, such as pigeons and sparrows, are considered clean. People’s habit of feeding pigeons around Masjid al-Ḥarām or other mosques and the fact that when a pigeon defecated on Abdullah Ibn Umar, he wiped it and performed his prayers demonstrate that such bird droppings are not considered unclean.
According to Abu Ḥanīfa and Abu Yusuf, the droppings of the birds whose meat cannot be eaten, such as falcons, hawks, and owls, are pure due to necessity. This is because since they defecate in the air, it is difficult to protect one’s clothes and any containers from them.
The blood remaining in the veins after slaughtering the animal is considered pure. Therefore, it is permissible to eat the blood found in slaughtered meat since it is stated in the Qur’an that the prohibited type of blood is the “blood poured forth”.
According to the Ḥanafi school, the urine of house cats and mice found in water containers is impure. If only a small amount of such water touches the clothing, it is forgiven, as it is difficult to avoid. In like manner, when the small amounts of mud from the roads splashes on clothes, it is forgiven because it is difficult to avoid. It does not nullify ritual prayer unless it is known with certainty that it was an impure substance.
If the body of the corpse is clean, the water used for washing it is also accepted as clean. Otherwise, the water used for washing will be considered impure. However, the water splashing on the person who washes the corpse is forgiven because of the difficulty of avoiding it.
 Al-Anʿām, 6: 145.
 For more information, see al-Kāsānī, ibid, I, 61-65; Ibn Abidīn, ibid, I, 154, 188-193, 295, 323; al-Maydanī, Lubāb, I, 30 ff.; al-Zuhaylī, ibid, I, 101, 120; Bilmen, ibid, p. 55 ff.