On one occasion, Slezak opened a canister containing photographic film, only to spill moon dust that had collected inside. After all, judging by the photographs (below) and stories from Apollo astronauts, moon dust gets everywhere. The dust spilled over Slezak's hands and film magazine, so to avoid the abrasive dust from damaging the bare film, he used Scotch tape and towels to remove it. The tape, plus moon dust, was left hanging in his dark room.
Dusted: Commander Eugene Cernan inside the Apollo 17 Lunar Module, covered in dust after a moonwalk (NASA)
Later, as Slezak explains, he was presented with a poster with photographs signed by the Apollo 11 astronauts. Naturally, he did what most of us would probably do given the situation. "I added the little piece of Scotch tape with the moon dust on it," he said. "I thought that would be kind of neat."
Not thinking he'd done anything wrong, Slezak sold the poster, plus tape, plus moon dust, in 2001. The buyer was a German collector who, seeing a profitable opportunity, removed the tape and cut it up to be sold in sections.