For new or set-in stains, create a vinegar cleaning solution consisting of one part white vinegar to one part water. Vinegar neutralizes the ammonia smell of urine without fading carpet fibers, making it a good choice for cleaning and protecting your carpet.
MORE: Tips to Keep Your Carpet Clean With Pets
Slowly pour the solution on the stained area of the carpet. The solution needs to reach the lower fibers in the carpet to completely neutralize the area. After allowing the carpet to absorb the solution for 10 minutes, use a layer of paper towels to soak up the liquid.
Once the carpet is almost dry — which could be several hours later — sprinkle a little baking soda on the area to absorb the odor. Allow the baking soda to settle into the carpet fibers for about 15 minutes, then vacuum the area. This should remove pet urine odor from the carpet.