When you return something (especially if you bought it online), there’s a chance it’ll end up back on shelves. But there’s a much better chance it’ll end up in a warehouse that’s part of an industry called the secondary market.

“We walk into this ginormous warehouse, and it was more stuff than I've ever seen in my life,” said Annemarie Conte, deputy editor at Wirecutter. “Pallets stacked high, over six feet, and just rows and rows and rows of them. And from all different retailers.”

Conte decided to purchase a 450-pound pallet of Amazon returns and then sort through them for a Wirecutter story. She spoke to “Marketplace” host Kai Ryssdal about her reporting.

To listen to their conversation, use the media player above.