If you're like me, you received a lot of political propaganda in your mail box during the last presidential election. Fed up with it, I made a few corrections, added "Return to Sender" and sent it back to them.
The truth is that most of the return addresses are for anonymous P.O. Boxes. One or two returned won't make an impact, but if everyone sends their propaganda back, the USPS and UPS stores (and any other mailbox shop) will have to contact their owner since it's illegal to tamper with someone else's mail.
Tell the politicians that we don't approve of their message--Send It Back!
P.S. No postage required, though be sure to scratch through any barcodes printed below your address so the computer reader won't mistakenly send it back to you.