The mold is just on the paper. If I cut and remove the paper, the black mold will not be seen. Since the material under the paper was ever wet (but no black mold), it becomes a little soft in the surface. So I intend to remove the soft material and then use the joint compound to fill and patch it. After that, I will use the paper tape to cover it. Is it doable? By the way, is the ceiling board gypsum board? Can you identify it?