Years ago my wife and I spent a month in Austin, TX. and stayed at my brother-in-laws place. He had 2 cats and as soon as the door to the apartment opened you were overwhelmed with a stench that was arguably the worst smell in the world.I am, of course, talking about the nasty cat urine smell that permeated his place. Part of the problem was he didn't clean the litter box enough and the odor just kept building upon itself until virtually everything reeked of cat pee.To make matters worse, the cats were not happy about their dirty litter box and would let him know it by leaving little brown ...