We have several large (3' x 6') blackened areas on our hardwood floor where water damage occurred. This discoloration goes deep. Our goal is to sand the floors and apply a clear coat, but we first want to know if there is a product that will remove the black stain. Also, if this cannot be done will a dark stain hide the problem?
Taken from: http://www.wikihow.com/Get-Water-Stains-Off-Wood