Many paper/cardboard food containers (like coffee cups) contain a thin plastic liner to water/grease proof them. There's a Finnish company that has developed a

Many paper/cardboard food containers (like coffee cups) contain a thin plastic liner to water/grease proof them. There's a Finnish company that has developed a plastic-free coating: https://kotkamills.com/products/isla/ https://kotkamills.com/products/isla/