We're getting the strong impression that being in that Tin Man outfit was no fun at all. When your makeup wasn't giving you serious injuries, and you weren't wilting under the glare of the lights, you were getting covered in melted chocolate. The character of the Tin Man has a serious problem with rust and is frequently getting shots of oil on various parts of his anatomy to keep him walking, including all over his face.
In an interview given years after the movie, actor Jack Haley explained that they had to use melted chocolate for the purpose because oil wasn't showing up properly on the recording. The fact he made that statement implies that somewhere on the cutting room floor there were takes of Haley getting squirted in the face with actual oil before they realized it wasn't working. We hope he got paid danger money for this film.