N.H.
try apple cider vinegar. My mom has alot of cats and sometimes they dont pee in the box and so far it has taken it out of everything, even clothes that have been washed and dried. I myself am 21 weeks preggo and think everything smells but can never smell cat pee at my moms. It has worked on male cat spray too that is hard to get rid of. There is also a product called Natures Miracle that works and it removes the smell to the cat too so it wont pee in that spot again. Maybe if you try both the vinegar first then the natures miracle.
Oh the natures miracle needs to be able to soak in to the area and dry so just spot test it first.
Hope this helps Good luck