I do pretty much what Lemming does, except I use their own reply envelopes to send back a note asking to be removed from their list, after carefully crossing off all possible offers so they're sure I don't want to order anything. But that's a good idea, sending someone else's stuff back to them.

I produce publications for a university library, and after several years of suggesting we needed a reply envelope, I finally just went ahead and designed one, and have it inserted in each newsletter we produce. Since we don't send them out broadcast, but only to members of organizations on campus, they have a low annoyance factor. Every so often a cranky note comes back to take them off of our list (or to remove duplicates), but mostly they come back with money inside. It's wonderful (so there were no complaints about the expense of designing and producing them)! I have to be only *slightly* understanding of the person whose job it is to open those envelopes. One hopes they are in a position to forward their findings of the contents to someone in a position to care about it!

SRS