please help. how can you clear files from windows media player 10

hey I have Windows media player 10 and I need to know how to clear out the things I have played with WMP. When I click on file, about halfway down the menu are all the things I have played. I looked for a way to clear them but I couldnt find it. I need to know how to clear these. please help

[349 byte] By [rstevens] at [2007-12-22]