What I've been doing is adding User Defined Header Rules, like this:
From Contains .pw>
and scoring 245 points. I've done 245 points for .eu>, and .pw>, 25 points for .in> and .ru>, and 75 points for .info>
The > symbol is critical, do not leave it off.
It works great here, dumping thousands of .eu and .pw spams a day.
Thanks!! Step by step on doing this. Not available thisway in 7.6.
Why the smaller numbers for .ru and .in?
We have employees who have family in those countries. This just increases the score enough to quarantine the messages where the users can still see them, and release any personal ones.