Robert Otto’s Marilyn Monroe collection is not for sale. Not for $1 million or $3 million. “It’s not for sale at any price,” Otto says. At least not right now. Maybe he’ll think about it after “Marilyn: The American Treasure,” the exhibit he’s organizing, is over. Though its venue and opening date are up in the air (Otto says several Las Vegas hotels have been vying for the chance to host it), its content is not. It will follow Monroe’s career from its beginnings in the late 40s to her death in 1962 through work by five photographers (Otto won’t say who until the licensing agreements are finalized) and memorabilia from his own cache of more than 1,000 items.

Best of Chicago voting is live now. Vote for your favorites »

Instead he keeps his collection in a storage vault at a location he’d rather not disclose. Recently he made a visit to the vault–accompanied by a security guard–to pick up some highlights from the collection to show off. He brought back two tissue-box covers–one mock tortoiseshell, the other clear plastic–from the bathroom and bedroom of the house where Monroe died. “I also have her bathroom scale,” he said. He pulled out a pair of large rhinestone earrings. “These are, to me, so Marilyn: big, gaudy, glitzy. They’re clip-ons–she did not have pierced ears.” Then he disappeared into a bedroom and returned with a garment bag, which he carefully unzipped. “This is the dress that she and her mother bought together for Marilyn to go on interviews to the various studios when she was 18 years old,” he said, lifting a heavy black suit with a Made in Paris label out of the bag and laying it carefully on the couch. Purchased from another collector, “it’s probably worth in the neighborhood of $50,000.”

A gold plastic key chain with the number 624 stamped on it is from the Mapes Hotel in Reno, “where Marilyn stayed during the filming of The Misfits.” When the contents of the hotel were sold late last year, Otto was on hand; along with the key chain, he picked up an oyster plate Monroe is said to have used during her stay there. “This was not even something she owned. It was something she ate off of, and she ate off it over 40 years ago!” Nevertheless, after the Associated Press did a story about the plate last November, Otto got more than 900 phone calls–from media, fellow collectors, people selling more Marilyn goods. “The attention was amazing, but what it shows you is that Marilyn is still a story.”

In early 1980 Otto took a job as a human resources exec at Wells Fargo Bank in Los Angeles, where what he calls “the big collection” began. “In LA it’s everywhere. Probably every day after work I was going to antique shops, and on weekends estate sales. I lived in an apartment that was wall-to-wall Marilyn.” At a party Otto made the acquaintance of someone who worked at one of the movie studios–“20th Century Fox? Paramount? I can’t remember”–and after a few phone calls he found himself being guided through the studio’s vaults, which were full of Monroe’s costumes and props. “I felt like I was walking through a museum,” he says. “The most important part of it was not what was there but from my standpoint it clicks in that I need to get closer now. There’s a need to get closer, and jewelry and clothing will get you there.”

“There’s a final stage where you move from passion to obsessiveness about your collection,” says Otto. He reached that stage in 1991 when he bought a perfume bottle, one of two leaded crystal decanters that once sat on Monroe’s dresser, for $5,000. “If you buy what is known as a national piece, other collectors come out of the woodwork.” Especially for what Otto refers to as “things she touched–Marilyn DNA.”

Otto paid $125 in cash for the whole bin, then took his find to a photography studio in Hollywood that specializes in restoring old negatives. The restorer made a test that came out “beautifully–they’re absolutely gorgeous. There are shots of Marilyn with Joe DiMaggio walking in front of their home and three or four in the car. They look like paparazzi shots. We have no idea who the photographer is. This is a major surprise for the exhibit.