Complaint Review: Contest America Publishers

I made the mistake of playing the Free Lottos on the internet and the junk mail does not stop coming. Many look real nice and official ... the advantage of today's technology !

THANKS to Rip-Off Report, I didn't play the games:

Contest America Publishers, USA
Opportunities Unlimited Inc, USA

Pay a small fee to receive a big check? It just doesn't happen.
POBox addresses seem to be one of the main indicators too.

How do you get off their mailing lists and what can be done to warn others not to fall for these ? I have a pile of others I'd like to know about. Most are sweapstakes gimmics to sell some merchandise or jewelry, and foreign lottery plays.