WASHINGTON — It will take more than three clicks of the heels to restore the ruby slippers that whisked Dorothy back to Kansas at the end of “The Wizard of Oz.”

The slippers, which for more than 30 years have been one of the most beloved items at the Smithsonian’s National Museum of Natural History, were crafted almost 80 years ago by the MGM Studios prop department. Like most movie props, they weren’t built to last. Now, the frayed shoes aren’t even ruby-colored anymore – they’re more like a dull auburn.

On Monday, the Smithsonian asked the public to help save the slippers, launching a Kickstarter campaign to raise $300,000. In addition to restoring the shoes’ color, the money will go toward a technologically advanced display case that will preserve them for future generations.

The Smithsonian’s museums are federally funded, but the institution frequently solicits private and corporate contributions for major projects that its budget doesn’t cover. This is the Smithsonian’s second Kickstarter campaign. In 2015, the National Air and Space Museum raised $700,000 through the crowdfunding site to preserve the spacesuit that Neil Armstrong wore when he walked on the moon.

“This particular pair of ruby slippers really belongs to the American people, and so we thought as we sought support that we would invite the public to join us on this journey to help preserve them for the next generation,” said Melinda Machado, a museum spokeswoman.

The shoes are the most recognizable prop for the beloved 1939 musical, their deep red hue dazzling audiences when the movie made its dramatic transition from black-and-white to Technicolor. They have been on near-constant display since they were anonymously donated to the museum in 1979.

Preserving them is more complicated than it might appear, Machado said. The slippers contain a dozen different materials. The gelatin-based sequins are a relic from the infancy of plastic. They also include glass beads and red felt on the soles that was used to muffle their sound when Judy Garland wore them during dance sequences.

“We’re going to have to do a lot of scientific research to come up with a treatment plan that is compatible with all of the different materials,” Machado said.

As of Tuesday morning, donors had pledged more than $38,000 on Kickstarter. If the museum does not reach its $300,000 goal in 30 days, no one will be charged.