In addition to being an annoying mailbox clogger, junk mail can lead to a lot of extra waste. Here are some resources to stop receiving junk mail in order to stay sustainable.
6 steps to get off mailing lists to STOP Junk Mail
Federal Trade Commission Consumer Information
Direct Mail National Do Not Mail List
You can also download Paper Karma, which will let you take a photo of the mailing with your smartphone, and then attempt to do all the unsubscribing work for you.