I'm glad to see that other people here remember Clutch Cargo! If I'm not mistaken, the man who invented the "human mouth superimposed onto a cartoon" technique passed away recently (I believe it was called "syncro-vox", or something like that). Conan O'Brien uses the same concept in some of his "interviews", where an enlarged photo of a famous person is show, with only the lips moving as Conan talks to the person.
I grew up in the Philadelphia area, and remember watching Clutch Cargo on Sally Starr's program on Channel 6. Not only have Saturday morning cartoon shows become a thing of the past, but so have local Kiddie show hosts such as Sally Starr (in Philly), Officer Joe Bolton (in New York), etc.