Not only have I never understood use of the word "harpoon" for "(mouth) harp," I never did, and still don't, understand what the damn thing was doing inside a dirty red bandana. The entire line is so wacky that I never even thought to wonder whether the banadana was around the guy's head, or tied around his neck, or in his pocket. The pocket probably makes the most sense.

Great song, nevertheless! I haven't sung it in years, but it was a mainstay of my repertoire throughout the 70s. Juat one more example to prove that lyrics need not be 100% rational or understandable for a song to be successful.