What is the proper usage of "flesh (or flush) out?"

Hey Matt-man:

1. What is the proper usage of "flesh (or flush) out"? Co-workers seem to prefer "flush out," but I maintain that "flesh out" is correct, as in "We need to flesh out the details of this proposal." Please advise on the proper usage and the origin. Does the phrase trace its origin to painting? 2. What's your favorite quotation by Yogi Berra?

-- Scootero, UTC

Do you work in the exciting field of sewage treatment, Scoot? If so, then maybe "flush out" has some relevance. It's "flesh out," of course, like, adding some meat to the skeleton of an idea. Luckily, no one has a clue about the origin, so I don't have to go through one of those stupid, improbable explanations. And my favorite Berra quote was, "Hey, Matt, here's a check for that $5000 you loaned me back in '53."