Jack Benny radio show 1/7/45 First Show with the Vault 

Jack prepares for the gang's trip to New York; Larry Stevens sings "Don't Fence Me In".
When Jack realizes he needs $5 for expenses on the trip, he opens his safe. The beginnings of the vault gag are here, with Ed, the guard, and lots of crazy sound effects. The vault gag was also used on television, notably in an episode of "The Lucy Show", but it was a perfect gag for radio, becoming more outrageous over the years.
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