Before bringing cardboard boxes to a recycling center, all noncardboard packing materials should be removed, the box should be flattened or broken down and the cardboard should be dry and uncontaminated by food waste. Wet cardboard can clog the machinery that is used at recycling centers, and it should instead be trashed to prevent contamination of other pieces in the recycling load. Cardboard items that have absorbed food oils or grease, such as pizza boxes, should also be trashed rather than recycled.
Cardboard that has absorbed food oils or grease is also biodegradable, so the environment is not harmed by trashing it. Staples, tape and labels on cardboard boxes are not biodegradable, but they are removed from the cardboard pieces at the recycling center. Waxy, coated cardboard should not be brought to a recycling center, and all Styrofoam and plastic inserts should be removed from boxes intended for recycling.
One ton of recycled cardboard saves 6.6 million BTUs, or 390 kilowatt hours of energy, as noted by Waste Management, Inc., an environmental solutions provider headquartered in Houston, Texas. The company also claims that more than 9 cubic yards of landfill space are saved with each ton of recycled cardboard. Landfills only stockpile trash, but recycling removes the trash from the environment and converts it to new and usable materials and products.