222. If the body of an animal is tainted with an ayn al-najÁsah like blood, or with a najis object, like najis water, its body becomes ÔÁhir once the ayn al-najÁsah has been removed. The same applies to the inner areas of a human’s body, like the inner areas of the mouth or the nose. For example, if a person’s gums are bleeding and the blood disappears in his saliva, washing his mouth will not be necessary. However, if false teeth come in contact with the blood, they should be washed based on obligatory precaution.
223. If particles of food remain between one’s teeth, and he starts to bleed from his mouth, the food particles will be ÔÁhir as long as one is not certain that the blood has come in contact with them. If the particles come in contact with the blood, based on obligatory precaution they will be considered najis.
224. If the parts of the lips or eyelids that come together when the mouth or the eyes are closed, come in contact with a najis thing, based on obligatory precaution they should be washed.
The same will apply to the parts which a person does not know whether they belong to the inner areas of the body or the outer areas.
225. If najis dust or sand settles on a dress, carpet or anything similar which is dry, and the thing is shaken in a manner that the sand or dust comes off, then it will not become najis even if a wet thing comes in contact with it.