PaperKarma is a free app, available for Apple and Android devices, that will opt you out of junk mail. Just snap a photo of the junk mail you don't want and you're done. PaperKarma will contact the mailer and remove you from its distribution list. You don't need to do anything else. Remember that junk mail often is sent out long in advance, so it may take awhile to see results. But just wait and you'll see that flood of junk slow to a trickle.