Plastic bags are everywhere: In 2002 alone, nearly five trillion of them were produced worldwide. They're so common, it almost seems like they grow on trees. However, the truth is that most of them are actually refined from crude oil and natural gas. They aren't biodegradable, and if they should escape from custody on the way to the landfill, it's all too easy for the wind to blow them somewhere they shouldn't be. For instance, plastic bags clog waterways and can choke wildlife. (See References 1, page 25) With that in mind, it's a good idea to find ways to reuse them.