How to remove fixed track lighting heads?

I know, they're called "fixed" for a reason. I moved into a new apartment recently and inherited a rather 80's guy track lighting system. Since it was made by Con-Tech, I'm not sure if I can replace any of the fixtures readily anyways, but I would at least like to be able to remove the fixed lights for a good cleaning. I've been up on a ladder for the last fifteen minutes trying to maneuver these things out without flat out disembling the whole track. Any help with this?