Waxed Cardboard Compost Wax = Plastic The “wax” that you can scrape off is actually polyethylene, a plastic that keeps the cardboard inside from getting soggy. Waxed cardboard is mostly used by retailers (for shipping produce). Glossy Is Not Waxed Glossy cardboard and paper is not waxed. If you can’t scrape the “wax” off with your fingernail, it’s most likely paperboard and therefore recyclable. Did You Know? 50-Year-Old Boxes Because of their chemical coating, waxed cardboard boxes can take up to 50 years to break down in a landfill. Annually we send 600,000 tons of them to landfills.