The heat has not been kind to some of the plastics on my machines.
What are these parts called, and what are their functions? how important are these things?

The Model B has a spring at one end of it, but I cant tell for what purpose? I had to take it off, because I cant close the door when its on.
The Comet II seems to be a softer plastic that has shriveled in an attic for who knows how long. I think the plastic goes along the underside of the play fields lower boundary wall?

Nishijin Model B
Warped Plastic.jpg

Comet II
Soft Plastic.jpg