How is a large mattress that is difficult to remove purified if a boy urinates on it?

Question:
He says: Honorable Shaykh, may Allah grant you success, if a boy urinates on a mattress or carpet, for example, how is this mattress purified, especially if it is very large and difficult to wash entirely? And if water is poured on the impure spot to purify it, the impurity increases and spreads, so how can purification be achieved?

Answer:
No, absolutely not; the matter is not difficult, it is very easy. If the mattress can be carried and washed and rubbed, then that is done to it. But if it cannot be done because it is very large or fixed to the ground, as it is now, fixed to the ground and cannot be lifted and taken, then water is poured on it and that is sufficient. Pour water on it and that is sufficient, and it is purified by the permission of Allah, like the ground if impurity falls on it or someone urinates on it, water is poured on it and it is purified, and this is sufficient.