Your own personal proof of this is Pepsodent's clean-mouth taste for hours.
7 seconds sound clip from the The Day the Earth Stood Still (1954) classic radio play.
You can hear this line at 00:53:16 in the radio play.
Quote context
[...]
- Pepsodent's new flavor! Pepsodent's new flavor! And a clean-mouth taste for hours!
- Yes, the big news is Pepsodent has a brand-new wonderful flavor.
- Grown-ups prefer it, but kids... Well, kids go crazy for it. And that's not all.
- Your own personal proof of this is Pepsodent's clean-mouth taste for hours.
- So try new Pepsodent White, or if you prefer chlorophyll, Pepsodent Chlorophyll. You'll like.
- And now, here's Mr. Cummings with our stars.
- And here they are, after two out-of-this-world performances, Michael Rennie and Jean Peters.
- Mike, have you ever seen any U.M.O.'s?
[...]