[Spambayes] Messages classified as spam

[Gary Smith]

nearly 100% of my unsure is spam. When I train, I tick 
the unsure as spam & click on train.

Often I find spam correctly IDed in the classifier but 
instead of being marked for discard the buttons in the 
spam column are ticked. I have been reassigning these 
spam to be discarded when I click on train.

It seems that if Spambayes correctly IDed the spam, 
I should just discard it. Would I be better to train it 
again as spam or should I continue disposing the spam 
when I train?

Thanks!

Gary