The minute you see the cat urinating outside of her litter box, clean up the urine. Blot up the urine rather than scrubbing or wiping it. Blotting will pick up the urine in its place, whereas scrubbing or wiping will only spread the urine around, making the problem worse. When using any cleaning method, always work from the outside of the stain toward the center to avoid inadvertently spreading the urine around more.
Find Old Stains
If you didn't see the accident happen and need to find an old stain — or the source of a strong odor — buy a handheld black light from a pet store. Simply turn off the lights and turn on the black light and you’ll be able to easily locate any older urine stains.
Use Vinegar and Water
Vinegar and water are successful treatments for carpet stains. Vinegar works to neutralize the scent of the ammonia that often is associated with cat urine. Be sure to test on an unnoticeable section of your carpet to ensure the vinegar won’t cause any additional damage. Ideally, your cleaning solution should be equal parts white vinegar and water. Apply the solution liberally to penetrate the area fully. Let it sit for a few minutes before blotting it up with paper towel or a wet vacuum.
Finish Up with Baking Soda
Sprinkle a handful of baking soda over the area after you’ve thoroughly cleaned it. In some cases, such as a first-time urine stain on a specific area of the carpet, the baking soda alone should be enough to remove any remaining odor or urine completely. For stronger urine stains and odors, you can mix a handful of baking soda with 1/4 cup of hydrogen peroxide and a teaspoon of liquid dishwashing detergent. Then, apply the solution to the stain and work it into the carpet. The hydrogen peroxide oxidizes and kills off the bacteria in the urine. Be sure to allow the solution to dry fully before vacuuming it up.
Try Enzyme-Based Cleaners
If you’re not interested in home remedies, then look for products that specifically contain enzymes. The enzymes in these products will actually “eat” the urine and its odor at a cellular level, essentially removing both the stain and the smell for good.