There are several reasons why the cat has choosen the carpet instead of the litter box. If the litter box is dirty is one reason. Scoup it daily. Periodically wash it with bleach. Changing litter brands can call the cat to the carpet. If you recently introduced a new pet to the household Mr. or Miss Kitty may feel threated. There could be underlying medical problems. Get your cat checked out by a vet. So, to get rid of the trouble spot, mix 1 part vinegar to 1 part water (1 cup vinegar 1 cup water) If the area is wet, blot it with paper towels until you extracted as much of the urine as possible. Pour the vinegar mixture on area and let it dry. Let it sit at least twenty minutes. If you have a wet vacuum you can speed up the drying process. Keep in mind cats have a keen sense of smell and the longer you allow the mixture to sit, the better. Next sprinkle baking soda over the area and drizzle with dishwashing liquid and water. (1/3 cup of dishwashing liquid and 1/3 cup of perioxide) Be careful with the peroxide. Drizzle this liquid over the baking soda. Scrub in with a brush or rag. Vacuum. If you are not sure where the stain is, use a black light to reveal Miss or Mr. Kitty’s mishaps.