To get rid of the smell I used "Nature's Miracle" (which really is excellent stuff). I poured some down and reached in to get rid of what urine I could. However it is very hard and I still get a whiff of urine from time to time. I think the only way to really get rid of it would be to clean the...
Not sure. I did a quick check at Home Depot when I was thinking about this and didn't find anything, but there may be something if you look for it online.
I had this problem and managed to solve it. I have two cats - one older one and one younger. One or both of them (I believe the younger one) was urinating down the vents. One cat was still using a litter tray, but one was also pooping in the dining room. They had both used litter trays at some...