Should I Replace Previously Damp Bathroom Floor Boards that are now Dry?

[jonathonpm]

I have just moved in to a house and the fibre board and floor boards in the bathroom have clearly been exposed to moisture before. I am happy to rip the fibre board up but is it ok to leave the floor boards? As can be seen from the pictures there is an out layer of black (mold?) where the moisture has been in the past, it is not damp now and the wood feels pretty solid. Where I have sanded the floor boards down a little the wood looks better. Is it ok just to lay new fibre boards or should the floor boards be treated or replaced? Any advice would be great.




sanded floor boards


Before and after sanding

[imghttp://imgur.com/O1HTFWK.jpg[/img]
Before sanding


Close up

[Conor333]

What did you do? Have exact same situation