How to minimise spam emails

Your internet service provider (ISP) may offer the option of blocking "known spam" but you may have to turn that option on yourself. Go to your ISP's website and see if there's a way to configure your email settings to deal with spam.

Also, If you have a .mac .me or Icloud apple account you can report spam to apple and they will help eliminate it

http://support.apple.com/kb/TS4019

they have helped me in the past also double check the bottom of the email to determine if there is an unsubscribe button