If you'd like to make way for new recordings or get rid of recordings that aren't relevant to your optimization efforts, you have multiple methods of deleting your user recordings from the Recordings Dashboard and within the recordings player.
Select the recordings that you'd like to delete, click on Recording actions, and then choose to Delete these recordings.
Select the empty box next to name in the header, click on Recording actions, and choose Delete these recordings.
When you click through to an individual recording, you'll be in the Recordings Player. Select the trash can icon on the far right to delete your recording.