Tracking Him Down
First of all, Clare was still alive, which was great. Second, they were able to contact him! Sloan called him up and told him the story of the wallet. They invited him back to the theater, which Clare remembered fondly, to pick up his belongings.
Total Surprise
When Sloan first called up Clare, he said, "Hey, sir, I think we've found their wallet." Clare responded, "But, I haven't lost my wallet!" Turns out, he did! Clare told a news reporter that he thought he was being prank called until Sloan laid out the situation to him. He couldn't believe it.