By the end of Halloween trick-or-treating, most kids have collected more candy than they could ever eat. But where to put the leftovers? One alternative is to sell it back -- even make some money doing so -- all for a great cause.

The Halloween Candy Buy Back program allows dentists and orthodontists across the country to take back extra candy by the pound. Over 2,500 practitioners have signed on to the program, finding a local office can be done by using the program's zip code locator.

The Buy Back was founded by Chris Kammer, a dentist in Wisconsin. His office currently offers $1 per pound of candy collected by trick-or-treaters. In 2007, the first year the program was expanded nationally, only 300 dentists participated.

Kammer said he started the Halloween Candy Buy Back because he found that kids in his practice were eating treats throughout the holiday season, and the extra candy collected on Halloween was stretched out to be eaten over many weeks. He believes that no child needs a shopping bag full of candy.

"The thought of that makes me shudder," Kammer said.

Where does all this leftover candy go? It is shipped to U.S. soldiers overseas, as part of care packages in Operation Gratitude.

Unsurprisingly, this idea didn't make him popular among kids in the neighborhood, even his own children told him it was "a terrible idea." However, after the first year was a success, the community warmed up to the idea. Kids were still able to eat and keep some of their sweets, but families could share any excess with troops.

Operation Gratitude ships care packages including items such as DVDs, personal grooming items and games. The group's founder Carolyn Blashek said the candy is a nice addition.

"It's a great morale boost for the troops," she explained. "It reminds them of home, but more importantly, to me, this provides the opportunity for every American child to say thank you to the military."