A start-up company called [Philadelphia Fry-O-Diesel](http://www.fryodiesel.com/ “Philadelphia Fry-O-Diesel Website”) is focused on making biodiesel fuel from restaurant trap grease. Thats the slimy, sticky gunk that collects at the bottom of restaurant drains. Most restaurants pay to have the stuff hauled away.

[Listen](http://www.npr.org/templates/story/story.php?storyId=6585629 “Listen to the Story”) (NPR)