Ito, Edith Wollin's example for "carrying coals to Newcastle" is by far
the much better example of using the idiom.... I have to agree that the
necessity of including an act of carrying is the very best use of the
idiom... I fear the idiom is misused in many cases by leaving out that
qualifier. We Texans very often use "that dog won't hunt" indeed. A
great one! Have you discovered "letting the cat out of the bag?" It
means telling a secret and/or spoiling a surprise.... it dates back to
16th century England when cats (which were plentiful and cheap) were
substituted for pigs (which were in limited quantities and quite
expensive) by dishonest merchants in the market... after a customer
selected a pig, the merchant would offer to place it in a sack/bag, and
would artfully substitute a cat. As a cat lover, this makes me shiver,
but times were indeed different. Best wishes. Gordon