They are just a pair of shoes, but what a pair of shoes.

Possibly the most famous footwear in America, a pair of Dorothy’s ruby red slippers worn by Judy Garland in the 1939 movie “The Wizard of Oz” are showing their age.

So the Smithsonian Institution, home to the slippers for nearly 40 years, is raising money to save them at an eye-catching cost of $300,000.

The money is being raised through a Kickstarter campaign, the online technique the Smithsonian has begun to use to expand its private fund-raising for objects that capture the public interest.

Last year, in its first such online campaign, the institution attracted $719,779 from 9,477 individual donors to enable its National Air and Space Museum to conserve, digitize and display the spacesuit worn by Neil Armstrong during the Apollo 11 moon landing in 1969 and Alan Shepard’s spacesuit from the first American manned spaceflight in 1961.