The basement of the prewar co-op on the Upper West Side was so cluttered and dark in one area that the staff called it “the Dungeon,” and last year, the building’s new superintendent resolved to clear it out.

For weeks, he hauled the junk left behind by former tenants — old air-conditioners, cans of paint, ancient elevator parts and rolled-up carpets — through the winding hallway with its low ceilings to the dumpster out back.

About halfway through the job, he spied an old tin can on a shelf next to a leaf blower. He read the label:

“Remains of Willy Ley. Cremated June 26, 1969.”

This was not the sort of thing you toss in a dumpster.

The super brought his discovery to the co-op board president, Dawn Nadeau. She had plenty of co-op business to attend to — a lobby renovation, a roof replacement — but the disposition of someone’s ashes was new to her.

“We needed to handle the remains as respectfully as possible,” said Ms. Nadeau, a brand consultant. “So I set out trying to figure who this was and who it belonged to.”