How to delete some audio files ?

Hello !
I'm used to post on french forum, witch is easier to understand for me ;-)
I've uploaded too much audio files on my airtime configuration. So Icecast2 and Airtime are not able to run correctly.
My problem is that I don't have found the way to delete some files... Can you help me ?
(Some files haven't be schedulled in airtime)

Thanks for this beautiful and useful tool !

BuzzRadio