I live out in the country and my landlord has 3 barns out here, so as you can imagine there are several pharaoh cats running around out here. My basement is outside access only and these cats have found their way down there. Now my problem is them using it as their litter box....the smell is coming through my heating vents everytime the heat kicks on, a very strong odor of cat urine fills my house! So, going to go down there to clean it up and find where exactly they are getting in from to close it off...my question is, would it be harmful to through some bleach water around on the cement? I know it is harmful to mix bleach and ammonia so I was kinda worried. The basement is half crawl space that there is really no way I'm going to be able to get into, any advice on getting this smell gone?????