If you want to delete a track on SoundCloud which was not uploaded by Label Worx, please see this article: How do I delete tracks from SoundCloud uploaded manually to free space?.
If you want to delete a track on SoundCloud which was uploaded by the Label Worx LMS, complete the following steps -
1. Select "Tools -> SoundCloud" on the top menu
2. Select the red cross on the right of the track you want to delete
3. Confirm that you want to delete the track when asked
NOTE : The track will be removed from the SoundCloud module, and your SoundCloud account.