Junk mail that comes with a reply paid envelope is great; it makes it very convenient to return the stuff to the offender, at the junk mailer's expense. It's not guaranteed to get your name off junk mail databases. Dealing with returned junk mail isn't a priority for most marketeers. Or at least not as much a priority as carpet bombing. Still, sooner or later even the most persistent junk mailer will get the message.

To encourage junk mailers to take your details off mailing lists you could try sending this Business Reply Pamphlet [Link to the website of Centennial Society removed as the website no longer exists, JB]. Sixteen images give step-by-step instructions (to junk mailers) on how to break free and live, let's say, a bit more in harmony with nature. To give you an idea of how this may transform the junk mailer's office, here are images 1 and 8…

Update

Sadly, the website of the Centennial Society no longer exists. There are a couple most images from the Business Reply Pamhlet in the Junk Mail Art section.