I'd say Ohio is a fair guess. I have lots of milk bottles from Ohio (where I dig) that abbreviate Ohio as O., just like the small letters in the middle.
Yooper
Madman,
I'm not 100% sure that's what the letters mean, but I've never seen random letters on a milk inside the main circle of text...usually they spell a city and state...that's why I think maybe the O is for Ohio. The C,C,S I'm not sure about. There are three major cities in Ohio that start with C (Cleveland, Columbus, Cincinatti), but I don't know about the S....
Yooper
Hey Mike, that milk is from Ohio, Cleveland to be exact. I can't remember what C.C. S. stands for. My grandpa told me at one time but it seems to have slipped my mind. [8|]
Madman those are really nice looking. Did you dig them? I just got the new Ohio bottle club milk bottle book. It lists them at $8-10. But it's hard to go by this price guide. For example they have a milk from my town listed at $15-20. If I had one I could easily sell it for $700-$850. Happy Digging!