If there are dried cat urine stains in your rug, the smell is still in the room. This will not only encourage your kitty to use the spot again, but also makes it unlivable for your two-legged family members. Completely removing the stain is the only way to stop the behavior and remove the odor.
Use a black light to find all of the urine stains and ensure that you get the entire area. Darken the room and scan the rug with the black light. Urine stains will be illuminated when you pass over them.
Combine equal amounts of white vinegar and water. Saturate the stain thoroughly with the mixture. Make sure every bit of the stain is soaked. Leave the solution in place for 30 minutes. After 30 minutes, blot the stain with clean towels until no more liquid is coming up. Change towels frequently as they are dampened.
Sprinkle baking soda on the stain in a thin layer. Combine 1/4 cup of 3 percent hydrogen peroxide and 1 teaspoon of liquid dish soap. Pour the mixture on top of the baking soda. Use a stiff brush to work the mixture deep into the rug. Allow it to dry for several hours. Once it is thoroughly dry, vacuum up the remaining powder.
Wash the rug in a washing machine if it is small enough to fit. Add 1 cup of white vinegar to the rinse cycle to remove any lasting odors. Dry the rug outdoors in a sunny location.