#1 Fun140
THERE IS NOTHING FUN ABOUT SPAM.
[1] Go to http://fun140.com/opt_out
[2] Log in using Twitter OAuth
[3] You will stop receiving Auto-DMs but there is one more important step:
[4] Go to Twitter Settings > Connections and “Revoke Access” for the Fun140 application
Thank you @Delbius, @BuzzEdition, and @AbsolutelyTrue
#2 Tweetlater
[1] Follow @OptMeOut.
[2] DM @OptMeOut tell them to stop it!
[3] Receive their DM confirmation
[4] Unfollow @OptMeOut