EClean - EClean can be used in defense against spam and UCEs by anyone with a POP E-mail account. EClean helps you to avoid unsolicited E-mail messages by hiding your mailto: links through encoding, plus as a pre-mail client using powerful self-maintaining whitelists it authenticates and quarantines legitimate E-mail, giving you the option of deleting UCEs before they get in your in-box. Options include challenge response, scheduling, etc.