We've always been able to get rid of ANY odor, eventually, no matter how bad, even if it meant refinishing floors with six coats of poly with vinyl flooring over it! But we have a 2 BR unit that some mentally ill people lived in before we bought the building. They had 5 cats. 

Here's what we ALREADY DID:

1. 2 hardwood floors, resanded, then before the 3 coats of poly were added, I brought in a backpack sprayer with bleach water. Then another with 2 different industrial odor removing agents (like odo ban and natures miracle I think). 

2. Sprayed 2-3 times with high volume backpack sprayer (removed baseboard covers and literally pressure sprayed each fin so it gleamed) Sprayed literally every crack and crevice with about every odor eliminating chemical known to man. 

3. Every surface, odor blocking primer, then 2 coats. 2 floors that had carpet, stripped down to wood floor, soaked like #1, 3-4 coats poly, luxury plank vinyl over that. 

4. 12-24 hours ozone machine

Still can smell it, especially on humid days. Not overwhelming any more, but unmistakable. Because cat urine is organic, will there come a day when it will finally go away on its own? There's not much left for us to do, and we've already put 16K into the apartment in renovations (4K was cleaning, disposal, and odor mitigation, believe it or not!)

Thanks for any tips, and quips and jokes welcome as well, haha!