It is gift return season — and while consumers returning gifts will almost certainly get a refund or an exchange in most cases, restocking those gifts isn’t always possible for retailers.

Electronics are among gift returns at the top of the list for not being restocked, especially those that have been opened and turned on but then returned.

“There is concern that the machine now has personal consumer information on it,” said Joe Hse at D.C.-based Optoro, which helps retailers maximize the value of returns, largely through third-party resale channels.

Apparel is also a return headache for retailers, because the chains often discontinue apparel lines after the holidays and no longer carry them.

About 5 billion tons of returns will end up in landfills this year. But there are ways consumers can minimize that.

“The faster a consumer can get that return back to a retailer, the more likely that product is still in stock for a retailer to make use of that merchandise and sell it to another consumer,” Hse said. “The other big piece is the product condition.”

Having the original packaging also minimizes waste.

Holiday returns could add up to as much as $90 to $95 billion worth of merchandise this year.