Usage: DEL [<range>|*|ALL]

This command will delete specified memos. DEL ALL or DEL * deletes all of your memos within the active folder, so use it with care. DEL ALL is deprecated, but still works. Use DEL * to delete all memos in a folder. When deleting specific memos, the argument passed can be an individual memo number, a comma separated list of memo numbers or a memo range. A memo range, denoted by the syntax <lo>:<hi> specifies that you wish to delete all memos, whose id is greater than or equal to 'lo' and less than or equal to 'hi'. This command will also delete a memo folder. However you cannot delete the INBOX, SYSTEM, or RECYCLER memo folders. You can only delete folders you created.

/msg memoserv del 1
/msg memoserv del 12:15
/msg memoserv del 2,3,6
/msg memoserv del *
/msg memoserv del all

Make sure that you have the correct folder active when you are deleting. Deleted memos will go into the RECYCLER folder, so you can move them back into your other folders if you made a mistake. Use the expunge command to make the memos in your RECYCLER folder vanish.