Tin Woodman
A recurring problem for the Tin Woodman in "The Wonderful Wizard of Oz" and afterward was his tendency to rust when exposed to rain, tears, or other moisture. For this reason, in "The Marvelous Land of Oz" the character has himself nickel-plated before helping his friend the Scarecrow fight to regain his throne in the Emerald City. Even so, the Tin Woodman continues to worry about rusting throughout the Oz series.