I removed a waterproof camping bag in my student appartment today that's been filled with stuff to find that it has left a moldy spot on the untreated plywood it stood on. It's been parked up right next the door/window.
I guess the damage has already been done since I think the white stuff may be mold, but is there anything I can do to minimise any further harm?
(It's darker than it looks in the picture)