sorry - obviously hadn't read the question correctly (put it down to my age) - you say you have used vinegar - having said that, I've worked in animal welfare for a thousand years and we have always used this with brilliant results..I'm not saying other things don't work - they probably do and very effectively too but once you have put anything on the area which contains chemicals -(particularly ammonia - and lots of sprays etc contain this) you are actually making the problem worse. If you get no success from other suggestions - wash the area thoroughly with clean water (several times) then apply a dilution of vinegar and water. I'd be very interested in your findings. Go well