[fetchmail] How do you drop BC mail?

Hi, I'm very new to Fetchmail and Linux.
I currently have Fetchmail setup to retrieve mail from my ISP and pump it
into my sendmail.  I have a very basic Mimedefang and SpamAssassin setup.  I
notice that a lot of spam is sent Blind Copy.  No one I know directly ever
sends me BC mail, so I would like to just drop it before it gets any
further.  Can I do this with Fetchmail and how if I can.  If it was in the
docs and I missed it, I'm really sorry and I will take my chastisement with
great humility.  But as you yell at me could you mention the page number it
was one.

Thanks