A few months ago my cat had a urinary tract infection and he was peeing all over the place, but he got meds and he got better. Unfortunately, when he was sick he peed in a corner and there's been a little bit of a smell there ever since. I've tried to eliminate the smell the best I could - cleaned it with Nature's Miracle plus sprayed comfort spray but now my boy is back to peeing there again!

I placed a litter box next to the spot, and he's sometimes going in the litter but he's sometimes also going in the corner, which is bad. He doesn't seem stressed out and he even has 2 litter boxes which are cleaned 1-2 times a day. He also doesn't seem like he has an infection again so my conclusion is that he still smells the old urine in the corner. Any suggestions for further odor removal? Suggestions welcomed!