No, Virginia, ovens were not always self-cleaning. And in 1965, this novel drawer-like device was the state of the art solution to the grimy chore. While it might have been an ergonomic improvement on the old way of doing things, I wonder [being a subscriber to the fewer-moving-parts-the-better school of thinking] what would happen if those ovens were jostled off their tracks or otherwise got stuck in the open position. Convenience turned into calamity!