In some ways, the overflow storage facility for the Detroit Historical Society isn’t all that different from a grandmother’s attic. There’s a bunch of old board games, tons of out-of-date clothing and dusty sewing machines. But that’s about where the resemblance ends. Chances are Grandma never had an iron lung, the arrow said to have killed Gen. George Custer or Mayor Coleman Young’s armor-plated limousine. “It’s magical in here,” said Elana Rugh, president and CEO of the historical society, talking in the warehouse officially known as the Collections Resource Center, a nondescript wood-frame building at Historic Fort Wayne. “There’s so much people don’t know.”