Rubicon and TerraCycle, both companies dedicated to managing and eliminating waste, recently teamed up to run a Halloween recycling initiative. The “Trick or Trash” campaign provides free lesson plans about recycling and the circular economy to elementary and middle-school teachers, along with bins, called Zero Waste Boxes, for recycling candy and snack wrappers accumulated by students during their trick or treating forays.

“Were tying it to Halloween because it definitely gets the kids’ attention,” says TerraCycle spokesperson Sue Kauffman. “It’s a perfect opportunity to teach some really important lessons about a topic that is really important to kids.”

While exact numbers of participating teachers haven’t been tallied yet, according to Kauffman, interest apparently has been high. Due to an unexpectedly enthusiastic response, the campaign had to end the box giveaway a few days early. Teachers and principals from more than 40 U.S. states signed up, more than doubling the anticipated number.

Those still interested in owning a Zero Waste Box can buy one on TerraCycle or Rubicon’s web sites. And the free lesson plans are still available. The initiative is being run through Rubicon’s site.

According to Rubicon, a whopping $2.6 billion will be spent on candy this year. Americans buy nearly 600 million pounds of candy for Halloween.

The lesson plans focus on what happens to all that candy waste after it’s tossed into recycling bins—what can and can’t be recycled, why you need to separate different types of waste, the merits of reusable packaging vs. single use, lifestyle changes that can lead to less trash and so on. “For a lot of people, when they throw things in the blue bin, it’s out of sight, out of mind,” says Kauffman. “They don’t really know what happens.”

Students are tasked with dropping off their candy wrappers and related waste after Halloween is over. Once the box is full, teachers can ship the box back to TerraCycle with a prepaid label. The company will then recycle the waste.

Atlanta, Ga-based Rubicon is a tech company focused on helping businesses, cities, individuals and haulers manage waste and become more sustainable. TerraCycle is a recycling and waste management pioneer, based in Trenton, NJ. It also recently launched Loop, which works with retailers and manufacturers to sell containers and other receptacles that are reused.

As for the Halloween initiative, according to Kauffman, it’s all about focusing on what students can do to change behavior and reduce waste. “If anything is going to change, you have to change the next generation,” she says.