Zippo lighters in good condition that were manufactured before 1955 and contain either unique artwork or a famous brand logo or slogan are among those that are collectible. Lighters issued by the U.S. Army during World War II are also collectible.
Starting in 1958, Zippo lighters were marked with a date code consisting of numbers, letters, slashes, lines and dots on the bottom to indicate the year of manufacture. This can help you ascertain whether your Zippo is collectible or not. Before 1957, Zippos were identified with a number of other markers depending on the year; for example, “Patent Pending” for 1933 and “Patent 2517191” for 1950 to 1957.