Q: Is there a product that will remove pet urine stains (black discolouration), which were found beneath carpet underlay? The floors are 51 year old oak hardwood, and large areas of the dining and living room are affected.
A: There are 2 component bleaches that would probably do the trick. Where to find them is any one’s guess. I haven’t used bleach in more than 20 years.
Related Q: In response to a question about using wood bleach to remove dark stains from oak flooring, you said you haven’t used that method in over 20 years. So what do you do to remove the stains?
A: I change the boards.
Related Q: You mention 2 component bleaches that might remove pet stains, but I don’t understand what you mean by this? Can you clarify? Would oxalic acid work?
A: The bleaches I used many years ago were composed of a gallon of part A and a gallon of part B. Extremely corrosive and would remove the red from red oak. Oxalic acid should work.