Made my own from a corugated plasic sign and duck tape.
Remove the old ones and strip them down to the frame. Cut 2 pcs of plastis sheet for each side, a "front" and a "back". for added strength the corugations on the front and back should run 90d of each other. Tape the frame to the inside of the front peice. Align the back piece with the front then tape them together. Wrap the whole thing in a layer of duck tape (color of your choice) and reinstall the visors.
They're strurdy, light weight, and waterproof (if a but ugly). I also made a camo cloth sleave for mine to match my interior.