Find animal urine stains in your carpet with this LetsFixIt guide! There’s nothing worse than having the elusive odor of animal urine wafting around your home. Our beloved pets can choose the darnedest places to go, and unless you happen to catch the spot while it’s still wet, urine-soaked areas can become nearly invisible. Animal urine will fluoresce under the glow of ultra violet (also known as UV or black) light. With just a little preparation, a black light can help you track down those hidden urine spots and eliminate the source of foul odor in your home.