To remove cat urine from a rug, use a black light to locate the stain, and blot the area. Combine 2 cups white vinegar, 2 cups lukewarm water and 4 tablespoons baking soda, and pour the mixture into a spray bottle. Spray the mixture onto the stain, and wait for five minutes before blotting the carpet to remove the cleaner. Allow the carpet to dry, and vacuum it thoroughly. Peroxide and baking soda also remove pet stains.
To blot the stained area, place a folded towel over the stain, place a heavy book on the towel, and stand on the book for several minutes to ensure the rug is as dry as possible before applying the cleaner. When using peroxide and baking soda to clean the stain, blot the rug as described, and apply a large handful of baking soda to the stain.
Combine 1/2 cup hydrogen peroxide and 1 teaspoon liquid dish detergent, and slowly pour the mixture over the stained area. Scrub the mixture into the carpet, taking care not to damage the carpet fibers, and allow it to remain for five to ten minutes before vacuuming the area. Repeat the cleaning process to remove difficult stains, or use an enzyme cleaner that is designed to remove pet urine.