This Instructable covers the time-honored art of sending refuse back to junk mailers in their own pre-paid business reply envelopes. What’s interesting, though, is in the comments on the Instructable one guy says that you can take the business reply envelopes and tape them to boxes and the post office will accept it! This greatly increases the scope, range, and weight of the objects that you can send back to junk mailers. Broken lightbulbs, bricks, this week’s trash, your imagination is the limit. (Don’t forget to visit optoutprescreen.com first to get yourself permanently off 95% of junk mail lists).
How to get some revenge on the credit companies [Instructables]
UPDATE: Actually, this only worked up until the mid-90’s. Now they’ve changed the rules. According to Post Office Domestic Mail Manual code 8.4.6, “BRM may not be used for any purpose other than that intended by the permit holder, even when postage is affixed. In cases where a BRM card or letter is used improperly as a label, the USPS treats the item as waste.”