Tried to bleach out some mouldy grout in the steam room where I have 2 wooden racks for sitting/toiletries, etc. New mould remover left some bleach marks on the wood (photos). I'm completely inexperienced in fixing this sort of thing (if it's even possible), so after some research it seems to me that my best chance is to sand it down maybe? I also have no idea whether the wood is treated - the planks are slightly different colour but when they get really wet there is some brown water dripping from them on the tiles below, so I'm guessing there has been some sort of a stain/protector applied. Do I need to reapply it after sanding on just the affected areas or on the whole thing? Thank you!