How can I get Evolution's Spam Filter to Work

[Schlaegel]

I recently switched from Thuderbird to evolution. I have since been
diligently flagging all of the spam I get, but to no avail.

I am simply running the evolution rpms available from fedora.

The spam I flag seems to permanently reside in the junk folder, but
new spam does not seem to automatically get flagged. Also, there seems
to be no way to automatically have the junk folder clean itself out.

So, (1) am I missing something to turn on automatic junk/spam
filtering, and (2) is there a reason to have evolution keep spam
sitting in my junk folder?

-Schlaegel