Animal or human urine on carpets, wood floors or mattresses can create an odor that stays around long after the stain itself has dried. Whenever possible, it's best to thoroughly eliminate the problem as soon as it happens. How you do that depends on what surface you're dealing with. In many cases, the solutions you need are already in your home. Test the solution on a hidden area first to make sure it doesn't discolor it.
Vinegar and Baking Soda
For pet odors in carpet, the trick is to neutralize the urine odor with vinegar, then neutralize the vinegar with baking soda. Start by mixing a 50-50 solution of white vinegar and water. Thoroughly soak the affected area, which will get the liquid down into the padding. Leave it for a few minutes, then pull out as much liquid as you can with a wet-vac. If you don't have one, keep paper towels pressed over the spot for a day. Sprinkle the area with baking soda, then work in hydrogen peroxide. Once it dries, vacuum up the baking soda.
Sodium borate--also known as borax--is a natural powder cleanser found in the laundry aisle. Traditionally used as a laundry additive, it's great for pulling urine odor out of mattresses without resorting to perfumey cover-ups. Don't put liquid on the stain, which will spread it. Blot it dry as much as possible. Sprinkle it heavily with borax. Work the borax into the mattress surface with a dry cloth. Let it sit for an hour, then vacuum it up. Repeat several times if necessary.
Urine odors that have soaked into hardwood floors present a special problem, because many alcohol- or acid-based cleaners that might get rid of the odor can damage the finish of the floor. Standard mouthwash, however, contains alcohol and other ingredients that help dispel the odor, yet it's generally mild and safe because it's made for your mouth. Mix a half-and-half solution of mouthwash and water in a spray bottle. Mist the area of the wood floor where the odor is coming from, and let it sit. Wipe it up after an hour and repeat until the odor is no longer detectable.