By saying "string-along songs about razor blades”, the author is referring to the fact that “radio-prize broadcasts” was sponsored by Gillette
Explanation:
Champion of the World is a chapter in the book I Know Why the Caged Bird Sings by Maya Angelou. The chapter describes a situation in which everyone is gathered in the store owned by the author's grandmother and her Uncle Willie to listen to a boxing match. In that event the author mentions the radio broadcast about razor blades.
