We are currently refinishing an old oak living room floor. We intend on staining the floor to a dark walnut, to more closely match the Brazilian Walnut flooring we have purchased for the kitchen. The floor is all sanded and ready for the stain, the only problem is that the oak flooring has dark spots that bleach, peroxide, or even oxalic acid will not remove. Do any one of you have any other suggestions on what to use to try to remove these stains, or any good tips on how to apply the stain to cover or blend in the dark spots? Thanks in advance.....