Finding the Cause of the Odor
Urine stains, especially pet stains, can be difficult to find because the pet may have gone absolutely anywhere in the house. The easiest way to find the cause of urine odors is a black light.
You can purchase a black light at your local party supply store or department store. Black lights, when all other lights in the house are turned off and the shades are drawn, will appear bright yellow on the carpet or furniture. Now that you know where the smell is coming from, you can get to work.
Vinegar helps remove protein from the dried urine that has settled into the carpet, floor or furniture. Protein is what keeps the smell intact in the area long after the urine has dried. Vinegar has a high acidity level that eats away at the proteins that have settled into the carpet or furniture. Prepare a mixture of one part water and one part vinegar and place it in a clean spray bottle. Cover the area with a mist of the solution, then allow it to set in for 10 minutes. Using a wet paper towel, dab the area for several minutes, then replace the paper towel and dab the area again. Continue to dab the area with clean, damp paper towels until the vinegar smell, as well as the urine smell, is completely gone from the carpet. After the carpet has dried, if you can still smell the urine, do the process again.
Baking Soda Remedy
Baking soda is an effective odor neutralizer and will absorb the odor from old urine stains. Sprinkle baking soda over the entire area, then add a few drops of hydrogen peroxide if it will not take the color out of your rug. Hydrogen peroxide can bleach fabrics, so test it out on a small spot in the corner of your carpet that will never be seen before attempting to pour it all over the center of your carpet or couch. Use a bristled brush to rub the solution deep into the carpet, then wait until the carpet dries completely. Vacuum up the solution, then dab with a damp paper towel if any residue remains on the carpet.