The famed host is auctioning off a number of items from his personal collection of musical memorabilia, including the microphone he used beginning July 9, 1956 -- his first day on the rock 'n' roll show that made him famous.
"It's tough to part with that one," Clark said of the microphone, which was valued by Arlan Ettinger, president of Guernsey's auction house, at between $10,000 and $100,000.
Other items to be sold include a bass guitar that Paul McCartney played when he was a Beatle, a beaded glove that Michael Jackson wore in his moonwalking phase and the harmonica that Bob Dylan played in "The Last Waltz."
Clark, 76, described himself as "a pack rat" since childhood and said his scripts and memorabilia had filled 28,000 square feet in a California warehouse.
"I've got every Life magazine that was ever printed, because my grandmother saved them for me," he said. "I've got most of the Playboy magazines. I've got Fortune -- lovely photographs in there. I saved everything."
Clark, who suffered a stroke in 2004, still goes to work daily and undergoes therapy, Ettinger said.
The auction was planned for Dec. 5-6 at Jazz at Lincoln Center in Manhattan. Guernsey's said it would be a no-reserve auction, with everything selling for the highest bid.
Much of the profits from the sale were to go to the T.J. Martell Foundation, which was founded by the music industry to raise money for research on cancer and AIDS, Ettinger said.