When your company gets the wrong mail delivered, either drop it back into the general mail box (as you would like others to do for you), or, if you are smart, use the opportunity to meet a new potential customer.
Return mail, introduce yourself and make a sales call. If the neighbor is nearby, pick it up and deliver it to them in person. They will probably be surprised and certainly will appreciate your effort. In the event they ask what your firm does, carry company literature and a salesperson business card to drop off. Tell them you are glad to get the mail forwarded to them and invite them to call your firm anytime. Tell them also that because they are in your neighborhood, you will do what it takes to get them a great price on their purchases with you.
Be a good neighbor; earn a new customer. Your efforts are appreciated, unexpected and a perfect way to reach out to a potential new customer. This is one of the best opportunities because there is very little reason you cannot be affordable and provide a great service or deliver great products in a timely manner. You are in the neighborhood. Do not miss these opportunities.
Teach your subordinates not to miss marketing opportunities. Teach your office personnel about recognizing these events as good possibilities to connect with new customers. Train the people who open the mail and tell them do not throw anything away until verified by their manager or superior. Hand delivering mail to the right recipient can go a long way and may turn the event into the gain of a new customer. That piece of mail may hold the key to a new account and is a great idea if pursued correctly.