Highlight 'Edit Messages', then press the center button.
Select the message to delete.
Utilize the 5-way navigation pad to scroll up or down to the applicable message.
Message is selected if a check mark is present. Press the center key to add or remove a checkmark.
Navigate to the applicable message thread(s) then press the center button to place a check mark next to the thread(s) you wish to delete.
If needed, press the center button to unmark the selected thread(s) for deletion or press the left soft key to choose Unselect All.
Press the right soft key to delete check marked messages.