Are your pizza boxes recyclable? Yes, maybe, no, it depends. There’s no easy answer to this question often posed by eco-conscious customers, especially after big events like the Super Bowl.

Nearly 13 million pizzas are sold on Super Bowl Sunday, USA Today reports. That’s great for the pizza restaurant industry, but it’s the kind of thing that worries recycling advocates. Fifty-seven percent of Americans believe their pizza boxes can be recycled, but the rest think the presence of grease and cheese on the box won’t allow it.

The matter seemed to be settled in July 2020 when the American Forest & Paper Association (AF&PA) released industry guidance resulting from a study conducted by WestRock, a leading pizza box manufacturer. The study found that the sticking point on pizza box recyclability—the presence of cheese and grease stuck to the box—wasn’t so sticky. “Pizza boxes are recyclable,” AF&PA President and CEO Heidi Brock said at the time. “Consumers should not be concerned about grease or cheese—simply remove any leftover pizza and place the box in the recycle bin.”

The problem is, many recycling centers still don’t accept pizza boxes. For example, the Metro Waste Authority website for Polk County, Iowa—which includes Des Moines and surrounding towns—offers a definitive statement: “Although it’s made of cardboard, pizza boxes are NOT recyclable. We all love the cheesy, greasy, good stuff, but that’s the same reason we can’t recycle pizza boxes. The grease and cheese stain the cardboard, putting it in the contamination category.” But the site adds, “If you’re a recycling superstar, you can rip off the top part that isn’t stained with grease and recycle that.”

But in Gloucester, Massachusetts, the Office of the Mayor urges locals to recycle their pizza boxes. “You can put your EMPTY box in the recycling,” the mayor’s website states. “Grease is OK.” And in Vermont, the Addison County Solid Waste Management District notes that “pizza boxes with a small amount of grease can be placed in your blue bin for recycling.” However, it requires that “any stuck-on cheese or leftover food” be removed before recycling the box.

Related: Here’s why pizza is good for you (no matter what anyone says)

According to the AF&PA study, pizza boxes “currently found in the recycling stream have an average grease content of approximately 1-2% by weight level.” That small amount of grease would have “minimal” effect on the recycling of pizza boxes. “Therefore,” the study concluded, “there is no significant technical reason to prohibit post-consumer pizza boxes from the recycling stream.”

A few months after the AF&PA study was released, Domino’s created an online tool that lets consumers enter their zip code to find out whether their local recycling facilities accept pizza boxes. But even that tool can yield ambiguous results. As an example, for Oxford, Mississippi (home of PMQ), the site states, “Recycling guidelines in your area suggest that corrugated pizza boxes are accepted. However, it is not stated explicitly. Studies have found that empty corrugated pizza boxes are technically recyclable. Recycling guidelines in your area should be updated to explicitly state their acceptance.”

The Paper and Packaging Board maintains that pizza boxes can be recycled “even with a little grease and cheese” as long as remaining food scraps are removed first. With this year’s Super Bowl in mind, the Paper and Packaging Board issued a February 1 press release noting that 10 states and the District of Columbia “shine as pizza box powerhouses where at least 90% of residents can recycle their pizza boxes.” In addition to D.C., those states are Alaska, Connecticut, Delaware, Maine, Nebraska, New Hampshire, New York, Rhode Island, South Carolina and Vermont.

According to USA Today, “If you live in the Northeast, chances are higher that you can empty and flatten the box and add it to your recycle bin,” but “if you live in the South or Midwest, chances are lower.”