How to Politely Ask Someone to Stop Sending You Junk Email
What do you do when someone known (like a friend, relative or a work colleague) starts to spam your email inbox. They regularly forward you all kind of junk emails but you can’t block their addresses because one out of their 100 email messages may be useful.
Now if you know the person, a possible solution is to send him a polite but firm email asking him to stop sending you all those annoying and forwarded email messages.
If you are feeling a big hesitant to do this on your own, a free service called StopForwarding.us can help.
Stop Forwarding will send an anonymous but polite email to your friend requesting him to refrain from sending junk emails. This mail is sent anonymously so no hard feelings.
Here’s an excerpt: "Avoid sending forwards to friends or relatives that you’ve grown distant with. It can be frustrating for the recipient when the only correspondence you have with someone is via impersonal, unwanted email" - Thanks Geeksugar.

Thanks Amit,
This should be a real end to those annoying people.I have already send mails to few.Waiting whether this could be a true solution and can help me out as my bulk folder daily gets filled up as a dustbin.Well once i succeed by this i will forward to all annoyers.
I wasn’t very successful by clearing my email box. I am getting more and more ’selling offers’. I have a strong feeling, that after I politely asked for stopping all, but personal emails, my friend just gave my email address to some other people I don’t know (that is my opinion, which is not proved). Problem is, because I’ve been using that private email account for so many years and really rely on it..
This is so cool. I sent it to all of my friends. It’ll keep them guessing for months wondering who sent it!- HoosierdaddyinFL
Just spent time sending the email to my friends who work in India’s biggest corporate company and yet find time to send 100+ junk email forwards a day!
Phew.. saved my time ;)
I need to test it..I dont think so this can stop spammers..
“This mail is sent anonymously so no hard feelings.”
Unless you’re the only one the sender is forwarding his spam to!
Just block them. If they need you they’ll figure out you’re not responding and will contact you some other way. Then they’ll be ready to listen why they got blocked. Otherwise they’re not ready for the lesson.