The material to make sun/rain/snow shields is called 'corrugated plastic board', sometimes called sign board. 20"x30" and 4 millimeters thick. Made by Elmer's. Easily cut with a razor knife. Can be attached with hook & loop type material. The black version passes my UV reflectance test.
Doubled up cotton pipe cleaners are treated with essential oils ( pine, fir, spruce, cedar ) and inserted into several flutes of the sign board. There is risk with essential oils. They are expensive and if the vendor cuts them with vegetable oil to boost profits, you will draw in a bear due to vegetable oil. A little essential oil goes a long way.