I was gifted my old parents bookshelf that's the oxford Huntington hardwood one in the pic. Problem is one of the shelves had a green spot that might be mold. I tried scrubbing it off with mold spray but it didn't remove everything. Should I scrub it with sandpaper? I don't know where I can buy shelves that would be the same color and hardwood. The shelves dimensions are 9.5 inches in length and 21.5 in width