Skiddoo, age.

Was looking for a good translation for the postcard and found this "skiddoo"; never heard before, wikipedia describes it as follows:

"23 skidoo (sometimes 23 skiddoo) is an American slang phrase popularized during the early twentieth century, first attested before World War I and becoming popular during the 1920s. It generally refers to leaving quickly, being forced to leave quickly by someone else, or taking advantage of a propitious opportunity to leave, that is, "getting [out] while the getting's good." The exact origin of the phrase is uncertain."