ATLANTA -- Curtis Wright pulled into the parking lot of the U.S. Postal Service Mail Recovery Center in Atlanta one recent morning, not sure what oddities he might take home.

At earlier auctions, Wright had driven off with a jack hammer, a Japanese sword and something he thinks might have been a sludge pump.

"I sold it on Ebay for $200 and I didn't even know what it was," said Wright, who lives in Auburn. "You never really know what you've got until you open it up."

Such are the vagaries of the bi-weekly auctions at the mail recovery center, where bargain hunters hope to buy undeliverable parcels that they can resell for a profit on Ebay or Amazon.com, at flea markets, or through brick-and-mortar retail shops. For some, it's a sideline to supplement income. For others, it's a livelihood.

Bidders come from across the country to the cavernous warehouse, one of only two mail recovery centers in the U.S. and the only one that holds auctions.

It's the final destination for clothing, jewelry, electronics, books, CDs, appliances, auto parts, sporting goods and every other package that can't be delivered or returned to its sender.

"This," said Sue Tedrick, manager of the mail recovery program in Washington, D.C., "is the very last resort."

The mail recovery center once went by the more romantic-sounding name: Dead Letter Office. But that title, which dates from 1825, was dropped in 1994 because it gave the impression that postal employees weren't doing their darndest to deliver the mail.

The mail recovery center's work still involves letters, but they don't go to auction. Only parcels do.

Would-be bidders are allowed to inspect the lots of merchandise for 60 or 90 minutes before the auction. After that, the room is closed and guarded by two uniformed police officers as the auction unfolds.

In many cases, the sneak preview isn't much help to bidders. Most items are piled in canvas mail hampers - you bid on the bundle, not the individual items - with shrink wrap over the top to seal the contents.

No touching is allowed, and what's underneath the top layer can be a surprise - good or bad.

"Sometimes you get the tubs (containers) for the minimum and you can make a few bucks. Other times you'll pay $800, $900 and get stuck with crap," said Lori Coppeak.

She mostly buys books and then resells them online.

"You've got to have a little gambling in your blood to do it," added Jill Parker, a regular bidder who on this day bought 80 pounds of children's DVDs, CDs and VHS tapes for $4,000.

"You don't want to go home with nothing," she explained.

With all of that lost mail, your chances are pretty good of finding something.

Last year, about 82 million pieces - about 1 percent of all mail - passed through the center. That included about 3 million parcels.

Packages are held for 90 days. If no one comes forward to claim the item, and if workers can't find a return address, the parcel is packaged with similar merchandise and put up for auction.

During bidding, competition becomes fierce, and when the prices rise, the tactics can take a turn for the nasty.

At one recent auction, a man who identified himself only as a bidder from Kansas noticed that three men in the back of the room seemed to be in cahoots. So the man from Kansas joined the bidding - even though he had no interest in the lot.

The bidding rose. And rose. And rose. The man stayed in - and helped drive up the bid -?until it hit $46,000.

Then he got out.

Why'd he keep bidding?

"Those three ... back there are working together," he said, angrily.

For all the competition, friendships develop.

Coppeak and Parker are downright chummy, sitting together during auctions and comparing their purchases afterward, even though they trade in similar merchandise.

"Lori says we compete with each other but we're buddies," said Coppeak.

Wright agreed: "There's always rivalries, but we're friends, too. We come here for the camaraderie."

Wright's wife, Cindy, isn't having any of it.

She knows why everyone is there, bidding hundreds - thousands - of dollars for that hamper full of blood-pressure monitors and extension cords.

"It's a habit," she said, laughing. "We're addicted. Don't try to sugarcoat it."

David A. Markiewicz writes for the Atlanta Journal-Constitution. E-mail: dmarkiewicz AT ajc.com