The term 'Mail Box Opening' refers to the job of opening mailboxes and retrieving the mail inside. This job requires a person to have a SLOT, which is a four-letter word. The SLOT is used to insert a key or other tool into the mailbox in order to open it. The person performing this job must be careful to not damage the mailbox or its contents. This job is often done by postal workers or other people who are responsible for delivering mail.