The National Sheriffs Association which is the group behind the neighborhood watch program puts out a variety of personal safety tips as well as home security tips including these mail theft tips. One of the most popular ways for thieves to steal your identity is through your mailbox. 1. Don't leave outgoing mail in an unlocked mailbox. 2. Take your mail to a blue collection box or your local post office and don't leave your mail in a collection box that is full. 3. Pick up your mail right away...