While the provided sources indicate this is a common cleaning issue, they do not offer specific methods. Based on general cleaning expertise, there is a reliable process for removing urine smell from a sofa.
The first and most critical step, especially for a fresh stain, is to absorb as much of the urine as possible. Using a clean, dry cloth or paper towels, blot the affected area firmly. Do not rub the stain, as this can spread the liquid and push it deeper into the upholstery and cushion foam. Continue blotting with dry sections of the cloth until no more moisture is being absorbed.
Next, you must neutralize the odor-causing components of the urine. The most effective solution is an enzymatic cleaner, which is specifically formulated to break down the uric acid crystals that cause the persistent smell. Thoroughly saturate the stained area with the enzymatic cleaner, ensuring it soaks as deeply as the urine did. Follow the manufacturer's instructions, which typically involve letting the cleaner sit for a specific period before blotting it dry. If an enzymatic cleaner is not available, a solution of one part white vinegar to one part water can serve as an alternative to help neutralize the ammonia.
After the cleaning solution has been applied and blotted, you can further deodorize the spot. While the area is still slightly damp, sprinkle a generous layer of baking soda over it. The baking soda will help absorb any remaining moisture and odors as it dries. Let the baking soda sit until it is completely dry, which may take several hours or overnight. Once dry, vacuum up all the powder residue thoroughly. For deep or set-in stains, this process may need to be repeated, or you may need to consult a professional upholstery cleaner.
