Rules state that metal is prohibited anywhere on the rocket or parachute payload system. Is Mylar acceptable as a parachute material? Considered metal?

Mylar is a type of plastic so it does not contain metal, however foil coated Mylar balloons are coated with aluminum metal. Pure non-metallic coated Mylar is allowed. Foil coated, metallic Mylar is not allowed by the prohibition of any form of metal in rule 3.d.