Homeless people use old newspapers to insulate themselves against the cold. My usual cycling footwear loses heat and my toes are often chilly by the end of my daily ride. I made booties from old newspaper to cover my shoes, and my toes were still warm at the end of my ride. On my test ride, I was out for an hour and fifteen minutes. The temperature was 23 deg. F. with a wind chill of 12 deg. F.
I placed a section of newspaper 12.5" x 22.5" on the floor. It was six sheets in thickness. I put my foot onto the newspaper a bit off center to rear of the fold. I pulled the front edge up over the toe of my shoe. I folded the front corners in and over the toe of the shoe. I taped them in place with a few inches of masking tape. I folded the back corners up and around my heel and taped them in place. I put my foot into a plastic grocery bag and wrapped it loosely around my ankle. Another piece of tape held it in place. Then I repeated the process for the other foot.
My pedals are metal rat traps with toe clips. I rode outside the clips with the clips hanging down. My feet never slipped on the pedals. If you want to clip-in, you could cut an opening on the bottom of the newspaper booties, but that could also increase the air exchange and make your feet cooler.
I was concerned that the plastic bags might get caught in my chain or on some sharp corner, but that was not a problem. The paper booties were moist at the end of the ride from perspiration, but still intact enough to use a few more times. For colder weather more sheets of newspaper could be used to make thicker booties.