Conversation so far:
When did MC Hammer begin his music career?
in 1986
What was the group name?
Holy Ghost Boys
How long did MC hammer  stay with the Holy Ghost Boys?
What else did you find interesting about MC Hammer?
With exception to later remixes of early releases, Hammer produced and recorded many rap songs that were never made public

Question: Why weren't they made public?
Self-contained rewrite: Why weren't hammer produced and recorded rap songs made public?