I am trying to clean 2 of the big grey plastic type Brower Top Hatch Incubators. I can not for the life of me figure out how to get the black egg separator tray (the one that looks like an old wagon wheel with spokes), off of the center grey tube. If anyone knows what I am talking about please help. I need to get that black spoke wheel thing off so I can get to the egg tray etc. down below it. Is it not meant to come off???