What is the ruling on the substance that comes out of the navel during ghusl from janabah?

If the substance coming out of the navel is blood, pus, or serous fluid that amounts to the size of a dirham, then it is impure (najis) and must be cleansed during ghusl. It does not, according to the more authoritative opinion, invalidate wudu. If it is a small amount, less than a dirham, then it is excused. However, if the discharge is accumulated dirt deep within the navel, it is not impure, but it must be removed to ensure that water reaches the area during the obligatory ghusl.