If one man’s trash is another man’s treasure, what about one San Diegan’s stained Skylab coffee mug. “Somebody will want this,” said Allen Haff, peering into the mottled depths of a commemorative mug from the 1970s. And that Skylab mug was just the tip of a large and semi-lucrative heap. In “Auction Hunters,” as in the A&E network’s “Storage Wars,” potential buyers bid on storage units after just the briefest look inside, and the unveiling of the mystery purchases is the main source of drama. Along with fellow collectibles’ expert Ton Jones, Haff is the co-host of “Auction Hunters,” the Spike TV reality show chronicling the duo’s adventures in the storage-locker auction trade. “When (the units) were good, they were really good,” said Jones. The boyish Haff and the tattooed Jones spent the past week bidding on the contents of San Diego’s defaulted storage units for episodes to air in the show’s second season, which returns with new installments on Tuesday. Just how good and bad, Jones and Haff aren’t at liberty to say.