Register with the Direct Marketing Association to remove your name from its national mailing list. The service is free if you register online, or $1 by mail.
Reject preapproved offers from credit card companies by visiting https://www.optoutprescreen.com/ or calling 888-567-8688.
Sign up free at http://www.catalogchoice.org, and the site will do the grunt work to get you off mailing lists for catalogues you don't want.
Pay a $20 annual fee, and GreenDimes will remove your name from catalogue and other direct-mail lists, plus plant up to 10 trees.
For $41, 41pounds.org-- named for the weight in junk mail the average adult receives each year -- will contact several dozen direct-mail companies on your behalf. In addition, $15 of your fee goes to your choice among the group's nonprofit affiliates.