There was something on the news last week about if a woman drinks 4 cans of coke a week it can decrease the bone density in her hips. Only coke though, not any other carbonated drink, and only women and not men. Could this be what you heard?
I've heard it reported that the Americans used coke to clean gun barrels during the second world war. Perhaps I was being 'wound-up' as a young lad in the 1940's.
I have seen guys who had corrosion on their battery cables in their car - where they connected to the battery - they poured Coke on it and it took the corrosion off.