Most messages which arrive in my ACS network mailbox are either not relevant or are just spam. Yet there is no apparent means of deleting them. Does anyone know how to do this?
If you are talking about your inbox I would recommend clicking on the "View Unread" so anything you have read disappears from your list. Its not a true mailbox with mail, but rather notifications so although many are not useful to you, they aren't actually SPAM.
I hope this is helpful.