Urine has salts that do NOT dissolve in water or cleaning solutions.
When an area is cleaned the ammonia in the salts are often reactivated, making the area smell worse.
There are hundreds, if not thousands, of pet products that claim to work and 99% they will not work.
Deodorizers - Masks the smell for several hours, sometimes longer. After the fragrance wears off the smell will still be there.
Ozone - Only purifies the the air. Does nothing to the urine contamination. After ozone is shut off approx. 1 hour later it will still smell just as bad.
Enzymes - Fairly effective on cat urine, excellent on dog urine if used probably and extracted. Natures Miracle is a joke. A good Enzyme is cloudy and will look like milk indicating it has a high amount of Enzyme and Bacteria. Natures Miracle is clear. Enzymes can only be used on synthetic fibers. A much better enzyme is "Urine Off." Enzymes need time for the biologic process to take place. Urine is food source for enzyme and will need at least 3 days dwell time for it to be effective before Hot Water Extraction. Make sure you treat with enough "Urine Off" to contact all of the urine. Directions are on bottle
X-cide - is based on Chemical encapsulation supported by Pairing agents and Physical encapsulation.You will choose this product when you are treating odor transfer to upholstery such as when a pet has encountered a skunk or rolled in some odorous substance and then rubs against upholstery. You will also find it to be a good and expedient treatment for pet bed areas to remove the body odors. This is a good choice for carpets or other surfaces when the odor is in a well defined source, small deposits that can be quickly and effectively treated.
XCIDE is very easy to use and fairly effective on cat urine and very effective on dog urine. Spray areas with Xcide, rub/agitate into fibers, let it dry and follow with Hot Water Extraction.
Blacklight - A blacklight or uv light will help locate the urine at nightime.
I would recommend trying X-cide because it easy to use and you don't have to wait several days, like enzymes, for it to work.
Also, keep in mind that urine may have soaked into the cushion below. Don't make any guarantees.
It may take some trial and error to become a pet odor removal expert.
LINK FOR X-CIDE BELOW..... Odor Zyme would also be a good enzyme to try... I wouldn't waste your money on the other products. Some do nothing to remove the smell and others cannot be used on upholstery in cars.