An old wives' tale suggests pouring a capful of ammonia into the trash bag before putting it on the curb. The theory is that if an animal rips the bag open, he'll get a strong whiff of ammonia and run away. But here’s the problem: Ammonia is a strong irritant and can cause lightheadedness and burning of the throat, nose and respiratory tract. If you want to prevent animals from getting into your trash, utilize wildlife-resistant trash cans with tight-fitting lids. And if you do put your bagged trash out on the curb, do it the morning of trash pickup -- not the night before.