I have used vinegar and it does work to make it stop smelling TO US, but it doesn't get rid of the pheremones which the dog can still sense and make them want to keep going in the same area. I know a lot of people on YT use Nature's Miracle, but I haven't tried it yet! I did use something called Get Serious (
http://www.getseriousproducts.com/index.swf) and it seemed to work pretty well. I also have invested in a light that shows the pee spots, because sometimes you can miss them if they've been there and dried for too long!