Posted by Jesse (CO) on February 19, 2002 at 10:45:34:
You may want to consider other methods. My only knowledge of placing ads in mailboxes is what is stated by J. Burley in this link, maybe you can get a few other ideas from this to work out your advertizing:
“Beware: In the United States the US Postal Service considers it a felony to tamper with the mail. If you live in the US do not place your flyers or hangers in people’s mailboxes.”
Best of success!