If you’re interested in opting out of so-called ‘firm’ (i.e., pre-approved) offers of credit or insurance products then hop on over to OptOutPrescreen.com and let them know.
This web site is a joint venture by Equifax, Experian, Innovis and TransUnion, and it allows you to opt out from receiving firm offers for either a period of five years or permanently. You can also opt back in if you change your mind in the future and wish to start receiving these offers again.
Note that, while they ask for your social security number, you don’t have to provide it to have your request processed. Now before you rush over and opt out, keep in mind that doing so may cause you to miss out on juicy 0% balance transfer offers, etc.
From my perspective, the upside of not having pre-approved credit applications waiting to be stolen from you mailbox is well worth the loss of a few deals.