u/Heart_My_Kingdom

East Coast, USA. This is on carpet, in our foyer coat closet. It was under a bookshelf we had to remove, I believe the white part is paint from said bookshelf. We discovered this last week, no idea how long it’s been like this. I’m not sure what the black stuff is, whether mold or mildew. I don’t smell anything strong, it smells like any closet to me. I’m not touching it, I can’t tell if it’s seeped into the carpet or just on the surface. I have no clue how it got water damage, we never actually put coats in here, just store decorations.

Whatever y’all think it is, I’m hoping for advice for removal, especially whether the carpet can be cleaned, or should be removed and trashed.