When my kids were small, I would make up nonsensical lyrics to the “If I only had a brain” song from the Wizard of Oz.
My kids, in their 30s, can still sing them.
The two actors and the show's producer agreed to the switch. Here's an early photo of Ebsen as the Tin Man:
Unfortunately, 10 days after shooting began, Ebsen suffered a reaction to the aluminum powder used on the Tin Man makeup; he'd breathed it in, and it got into his lungs. That's how Jack Haley got the part.