It didn't look rusted, I just think that the small wire was caught in the threads. I was able to get the front of the spring started out, but couldn't get it to completely release and I didn't want to mess it up.
I have found that carb-n-choke cleaner sprayed into the hole a few times will quickly flush out the hard oil/grease. I have a hat pin that has the very tip bent to 90 degrees. Just screw it part way into the spring and pull from the outside. Works every time for me.