Could always hang, mount, tape or figure out some way to put "Mylar" up. Providing a link to give you an idea of what I'm talking about.
https://www.amazon.ca/VIVOSUN-Mylar-Diamond-Highly-Reflective/dp/B01N7P96NN/ref=sr_1_1?keywords=mylar+thick&qid=1587511526&sr=8-1