Whether it's a DVD they already owned, or a sweater that's way too big, the day after Christmas is when people flock to stores to make their returns.

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Edgar Dworsky of ConsumerWorld.org suggests three things you can do Thursday, to ensure a smooth return experience: be familiar with stores' return policies, do not open the product or products you plan to return, and make sure any receipts are kept handy.

If you don't have a receipt, you could find yourself at the mercy of the store. In that case, Dworsky said a little extra politeness is always helpful.

"If you do that, you should do fairly well but don't expect that you're going to get cash back," Dworsky said. "In most cases, even with a gift receipt you're going to get an even exchange, a gift card, or you're going to get a merchandise credit for the amount that was paid."

Without a receipt, the store credit might not be worth the amount you would expect, but rather the lowest price at which the item was sold within the previous 90 days.

Knowledge of return policies is also very important, according to Dworsky. While you're waiting in line at any particular store, he suggests you familiarize yourself with that store's policy, and make sure you fall within its parameters.

Dworsky also said many retailers have special "holiday return" policies that can give you more time to head back to the store.

"But they're kind of cheap, and they don't put up signs all over the store," Dworsky said, "so you do not realize you might have some return rights into January."

Both Walmart and Best Buy have holiday return policies that extend into the middle of next month.

Ultimately, Dworsky suggests customers put off doing returns the day after Christmas and instead take advantage of post-Christmas sales -- which tend to be some of the best.

"There's going to be a lot of long lines with a lot of crazy people on them, tempers might be short, as the day goes on, of people working behind the counter," Dworsky said. "I would only go back the day after Christmas to wait in the return line if you know they only have one sweater left in large, and you were given a medium."

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