Shoppers spent more than $15.5 billion this Christmas on gifts on the Internet alone. Just imagine how many millions went to unwanted polka dot sweaters, electric nose hair clippers, and thigh masters. That wasted cash piled up under the Christmas tree. We've all had it happen to us. In fact, you had it happen to you this year. You unwrapped the pretty red bow and tore through the shiny paper on that present from your Uncle Mortie, and immediately, you had to put on your best poker face.

How did you know I needed a sushi roller kit? you exclaimed with as much excitement as you could muster through gritted teeth.

The problem is you don't eat fish sticks, let along raw salmon.

You can't be too sore at poor Uncle Mortie, though, and the other friends and family who gave you unwanted holiday gifts this season. Buying Christmas gifts is difficult work. Then again, getting rid of a doosie of a Christmas gift is no piece of fruitcake either. That is, unless you know how to use the Internet to return your unwanted gifts from the comfort of your own home or, better yet, sell them for better use.

You're probably wondering how it's possible to sell off Santa's slip-ups when you feel bad enough returning them. In most cases, your friends or loved one invested time and money into shopping for your gift. They browsed countless Web pages. They trudged through the mall. And they were sentenced to hard time in the cashier line. All of it they did to please you.

At the same time, however, your friends or loved one couldn't read your mind as Jolly Old Saint Nick supposedly can. They could never tell if you'd appreciate that coffee table book on coffee tables, or that matching set of plaid socks and necktie. They could only guess at your inseam or your blouse size, or whether you look best in blue or black. And they had no way of telling that your third cousin on your father's side got you the same exact gift. With no list of who was naughty and who was nice, Uncle Mortie and company added to the millions wasted worldwide.

This waste doesn't have to be. Your loved ones only wanted to make you happy with their presents. So it stands to reason that if their gift didn't do the trick-because it was the wrong size, a duplicate present, or completely off the mark-they would want you to fix the situation. Whatever it takes, they would want you to be happy, right?

That leaves you with two options. You could return the gift to the mega store or the maul-er, mall. You would join the thousands of your neighbors with the same idea, all of whom are cramming into your local stores and cash register lines to return their unwanted gifts. Then you would also have to face the thousands of bargain shoppers out there looking for those post-Christmas specials, a rush that lasts well through January.

What's worse, some stores won't let you return goods if you don't have the original credit card or receipt. That means you could at best be left with gift cards with expiration dates at stores that you may not like. At worst, you could be stuck with your gift, not knowing what to do with it.

Now you're seeing the light. No, it's not the light from the inflatable 12-foot Santa Claus and reindeer on your neighbor's front lawn. It's the light from your computer monitor: the Internet. Today's Web can link you with someone who will think Uncle Mortie's gift is a precious treasure. This person, whether they're in Peoria or Pawtucket, North Carolina or the North Pole, is willing to pay good money for it.

Classified Internet sites can link you to this person faster than it would take you to stow the sushi set up in your attic. The best classified sites out there will also be free of transaction and membership fees. What's more, they allow you to negotiate price directly with your buyer and plan shipping arrangements, all with privacy and precision in mind.

You'll end up with cash to buy that special something you really wanted. Your buyer will be pleased with Uncle Mortie's gift. Uncle Mortie, well, he'll be glad the gift he gave you, doesn't just sit in the attic.