Opt Out at OptOutPrescreen.com.
You can opt out from these offers either for 5 years, or permanently (by mail).
It won’t eliminate all of the offers, but according to MasterYourCard it took care of about 90% of their junk mail.
Ecological, and de-stressing.
The rest of the post at MasterYourCard is worth reading also–it’s about doing for yourself what the company LifeLock says it will do for you for $120/yr.