Just deleting them won't help. They send emails in the tens of thousands, just making up combinations of names. (This bit has been going on for donkeys years - I remember when I worked at a large office in centrel London getting cold calling insurance salesmen - they'd call the switchboard and ask for John Smith, switchboard would put them through...)
If the name doesn't exist then more often than not the ISP will auto-reply saying no such name - then they just strike them from the list. All others are therefore hits...
You should do what I've done, and lose your email address. I hardly get any spam now...
btw in case anyone wondered, due to being away and computer problems I failed to renew geoffmorgan.com, it went into redemption, I paid $99 to get it back but it was too late. You can mail me at geoff-at-geoffmorgan.co.uk until i get it back (not long now...). smokie-at-stones.com works too.