Binding posts on Nautilus 804S question

Hey!

I just purchased a pair of Nautilus speakers off of the gon and have a question. I know that you can use banana plugs with these speakers because I have seen it in other setups...What I am wondering is how you get the darn plugs out of the back of the binding posts?!? They don't seem to want to un-screw easily, and they get to a point where they just will not move backwards anymore...what do you do? Is there a special tool that I need or something? Please let me know.

Thanks!
Ben