Promising review: "Owning two older dogs, and frequently fostering dogs, I have particular life experience cleaning up after dog accidents in the home. Bless their hearts, dogs are still animals, and animals have to potty sometimes outside the confines of generally accepted locations (i.e., outside). One of the most difficult urine messes is when there are hardwood floors they tinkle on. A dog peed in a corner of my living room, which of course has parquet wooden floor tiles, and which of course, I did not notice until a day or two later when the pee had already soaked into the wood parquet tiles, causing swelling and deep odor. Thankfully, I found Nature's Miracle specifically designed for hardwood floors. I was skeptical that it would work as well as the reviews noted, but it truly worked better than any other brand of urine cleaner that I have tried. It managed to effectively clean the stain, and eliminate the odor, even though the mess wasn't discovered right away." —HelloReese
Get it from Amazon for $8.12+ (available in two sizes).