Strange emails

One of my email addresses (for recruiting) is being spammed to the tune of 100 messages a day. The “from” is all ASCII text, the message is repetitous ASCII characters and they all have web links to Korean web sites. This is driving my recruiter crazy. We are blocking some of the domains but some of them come from yahoo – we don’t want to block that site. I have replied to a few of these to see if they were really people looking for jobs – always get back mailer daemons – no such address. Anyone heard of this?? Any solutions?? (other than changing the email address?)