After about fifteen minutes searching we have some suggestions about food safe plastic sheets. High density polyethylene is good, and Low density is ok for plastic leaching harmful stuff into the water. These are milk jug and bread bag plastic, respectively. PETE (Polyethylene teraphalate) is for pop bottles. This info comes mostly from Annie B in a safe food website. All plastics do something in sunlight we would want to know about. In the meantime, we just won’t leave our collector out in the sun, wash it or let the first of the rain flow off it, a libation..