Ever wonder what happens to toothpaste tubes, pens, guitar strings, and even cigarette butts after they are thrown away? Traditionally, nothing. That is until TerraCycle began running programs to recycle previously non-recyclable waste streams in 21 countries. Here, Michael Waas, global vice president of brand partnerships at TerraCycle, explains the company's mission, the economics, driving recyclability, and how to build a playground from toothbrushes