Once a month the United States Postal Service auctions off the valuable stuff it cannot deliver at Atlanta’s Mail Recovery Center. But at a time of rapid change for the Postal Service, last month’s live auction was one of the last. The Postal Service is contracting out the auctions and moving them all online as soon as April. GovDeals, the contractor, says expanding the pool of bidders beyond those who could show up in Atlanta on a Wednesday morning will bring in more money for the cash-strapped Postal Service. Roger Gravley, the company’s vice president of client services and marketing, said GovDeals auctions in the past have shown a 20 percent to 40 percent price increase over live auctions. A subsidiary of Liquidity Services, Inc., GovDeals contracts with 5,300 governments to sell their surplus.