Side curtains

["Wiedemeyer" <boxweed@thebest.net>]

Does anyone know what the trick is to replacing the sliding plexiglas
windows in the side curtains?  I tried removing the old ones in every way I
could think of to keep from breaking them, like bending them in the middle
while pushing outward, pulling from the edges, removing the felt first,
etc., and I ended up breaking every single one of them.  I thought I would
try to get some input from y'all before I destroy the new ones!

Thanks in advance!
Bob