Q: One visitor asked, "What kind of bleaching can be used to remove dark pet urine stains on hardwood floors? Tried sanding but dark places are still visable."

A: I have used floor bleach years ago. Expensive and quite corrosive. I am not even sure it is available now or whether you would be able to buy it. Somebody sent me an email representing a product called urineoff, which they claim will remove the uric acid crystals from any material, but they don't guarantee it will return wood to a totally stain free look. Best bet is to replace the pieces that are damaged, provided it is not all over the place.