When a user reaches their quota limit and the duration for automatic cleanup has not been reached, users need to clean out some of their files. This right now is pretty tedious as the user has to go into their sent items/inbox and Action > Delete Attachments on each message. I wish there was a way for end-users to bulk delete by either specifying a time range, or having the ability to select multiple messages and then delete attachments from all that are selected. It is the same way for admins as well, we can delete the message/attachments but appears to only allow deleting one at a time.
