Sounds like you have tried everything I would have done. My wife a a few cats and they have been doing the same thing but we don't seem to have the smell. What kind of disinfectants have you been using? Maybe try something a little harder?
What's up guys and gals. My name is Matt, been into construction since I was in high school. I had planned on being a carpenter but ended going a different direction. Well I just recently bought a house and can't want to start the remodeling.