Recycling isn’t always as simple as tossing items in the correct bin. Municipalities have rules about what can and can’t be recycled, and if you ignore them, you could end up sending unnecessary waste to the landfill. Pizza boxes are an example of a recyclable item that can’t always be salvaged.

You may have heard that you can’t recycle pizza boxes, but that’s not entirely true. Most pizza boxes are made from corrugated cardboard, which is recyclable under most circumstances. The material makes up most paper products collected for recycling, according to the New York State Department of Environmental Conservation.

If you need to get rid of an unsoiled pizza box, it’s fine to recycle it. Things get complicated, however, when the cardboard is covered in food matter. Pizza boxes tend to soak up grease from the pizza inside them, and soiled materials can’t be recycled. While it is sometimes possible to wash food off recyclables, grease stains are harder to remove from paper products. If you decide to put the box in the recycling bin anyway, it could contaminate the items around it, creating more trash.

Committed recyclers shouldn’t take this as an excuse to skip pizza night. Even if the bottom half of your pizza box is stained, you can still rip off the top half and recycle it as long as it’s clean. And if you can’t bear to throw out the rest of the box, cardboard is perfectly compostable no matter how greasy it is. Here’s the truth behind more common recycling misconceptions.