Those are the parting strips. They are easily removed, held in by a single nail.. and probably a lot of paint.
MKB54Member since 04/08/11
Just to answer my own question.. I found the secret to removing these sashes posted elsewhere (http://bobvila.com/forums/Doors_and_Windows/posts/18...
I have similar Curtis windows in my 1941 bungalow. They work well, but need refurbishing and I can't figure out how to remove the sashes. I've remo...