Many emails I get can't be blocked on Yahoo but I have found if I go to "view raw message" and make filters using their email address domain and "return path" domain and say I want them to go to Trash. You can do this without opening up the actual e-mail because just opening an email to unsubscribe can send a message back to sender by "return path". This has really cut spam out of my accounts. I never get more that 5 spams a day now and most days I don't get any at all. I concentrate on filtering the "domain" not the 20 letter gibberish they use as the name of the person/business email address. It is crazy but I never find any new messages that I have filtered in the actual Trash, I just don't get them anymore.