ANN ARBOR, Mich. – A massive cache of musical treasures that’s grown to include a fragile harp-piano, the pioneering Moog synthesizer and the theremin used for “The Green Hornet” radio show has been shuffled over the years from a theater to an unheated barn and now languish, rarely seen or heard, in a Michigan storage vault.

Spanning centuries and continents, the instruments worth at least $25 million by their chief caretaker’s estimate are packed and stacked in an out-of-the-way storage room with water-stained ceilings. It’s hardly the environment envisioned for them when Detroit businessman Frederick Stearns gave the University of Michigan the base of the collection a century ago with instructions that the instruments be exhibited.

“The only way I can characterize it is Tut’s Tomb, because it’s been so forgotten about for so many years,” said Steven Ball, director of the Stearns Collection of Musical Instruments. “The collection has been in a holding pattern for 112 years. This is a national treasure – it deserves the dignity of either being properly housed … or to be dispersed in such a way that it could be.”

Such “orphan” collections pose problems for academic institutions, despite the prestige that comes with owning them. Kris Anderson, director of the University of Washington’s Jacob Lawrence Gallery, said he discovered a repository of nearly 1,000 forgotten paintings and other artwork spanning more than a century. He found out about the collection because its main basement storage space was being reused.

Anderson, a vice president with the Association of Academic Museums and Galleries, said numerous campuses have collections that aren’t part of universities’ museums and risk being discarded. Doing so would be an “irreversible decision to devalue … the history of the institution itself,” he said in a recent paper.

The Stearns Collection has never had a permanent home. Less than 1 percent of the 2,500 items in the collection is displayed in exhibit cases at the university’s music school and nearby Hill Auditorium.

Their out-of-sight circumstances pain Ball, who has a copy of a letter Stearns wrote before donating about 940 instruments in the late 1890s.

“Under no consideration whatever however would I turn the collection over the university except with the understanding that it should be immediately housed and installed,” Stearns wrote. “I would not consent to it being packed away for some future regent to mount to suit themselves or to neglect entirely.”

University officials recently committed up to $400,000 to create a climate-controlled storage space for the collection. Ball is grateful for that but said it underscores the bigger challenge: finding millions more and figuring out how the collection can be seen, heard and experienced.