You just finished a delivery pizza and jokingly announce to your family that you will take care of the “dishes,” by which you mean you will smash/fold the box into quarters and stuff it in the … where?
Do you put it in the garbage that goes to the landfill? No, it is cardboard, which is highly recyclable. So you put it in the recycle bin, right? No, it’s greasy on the bottom, and recyclers don’t want greasy cardboard.
It’s a quandary for the pizza loving green citizen. So, finally, the definitive answer: Cut out the greasy sections and put them in the garbage. The clean parts can go in the recycle bin. Why?
Most pizza boxes have recycling symbols on them and are made from corrugated cardboard. What makes parts of them non-recyclable is pizza!
Grease and oil are not much of a problem for plastic, metal and glass, because they are recycled using a heat process. Paper products, however, are recycled with water. Since water and oil don’t mix, that’s a problem.
Food is one of the worst contaminants in the paper recycling process because grease from your pizza box can cause oil to form at the top of the slurry, and ruin the whole batch.
Paper fibers cannot separate from oils leaving contaminants so when the water is squeezed out, the paper has spots and holes. This is also the reason used paper plates, napkins, and paper towels are not recyclable.
Also, be sure to remove any stickers from the recyclable parts of your pizza box and thrown into the trash too. Adhesives can also ruin the recycling process.
Another option for disposing of your pizza box is to compost it. While cardboard does compost, you should still throw the greasy parts in the garbage because oils cause rotting, which smells and can attract the wrong kind of bugs, which is not very good for your plants.
Simple answer: pizza boxes tarnished with food are not recyclable — unless you remove the tainted parts. Clean boxes or parts of boxes are.