Dear Sir, This is embarrasing to admit, however I must. My house is 100 years old. My basement is full of cracks and leaks but most of all when it rains, the smell of mildew and cat litter is all throughout the house. I clean the cat liter every two days. But, I cannot get rid of this smell. Please be direct and honest with your advice. Of course, I can't get rid of my little angels (cats).