There is no need to delete email addresses that have had a hard bounce. ResultsMail unsubscribes these for you. A hard bounce occurs when an email address can not be delivered because it either no longer exists on that email server or the domain itself does not exist. These are automatically unsubscribed from your list, so there is no need to delete. Deleting actually creates a problem because it makes it possible for you to accidentally import known bad addresses at a later date.
If you are attempting to delete email addresses that have had several soft bounces, you may export the list and then select just the email addresses and copy them. Go to Contact Options and select delete or unsubscribe and paste them in the box. Delete will remove them from your list, unsubscribe will flag them so they are never mailed to nor are they ever able to be re-imported and mailed to in the future. We recommend you use the unsubscribe option since you have determined you do not wish to keep attempting to deliver email to that address.