I don't know if USPS offers this service, but for Canada Post, you can tape down a note to the inside of your mailbox where the postal worker will see it to indicate that you don't want to receive junk mail. https://www.canadapost-postescanada.ca/cpc/en/support/kb/rec... And yes, it really does work when combined with https://www.thecma.ca/resources/consumer-centre/get-less-pri... - when you do both, including opting out from CMA with multiple first and last names listed to handle different variations or previous occupants, you end up getting very few pieces of junk mail over the years. I actually wonder if some of it is returned to sender at the Canada Post sorting facility.