Was that what it was called, milk monitor? I think so, and that's the title in my mind.
Once upon a time, when young AC was in elementary school, a family could opt to have their children be supplied with a pint of milk per day, about halfway through the morning. It was delivered to the school [fittingly] in pint-sized, glass bottles and then put into portable wooden crate: one per class. Each week it would be some lucky student's turn to collect the milk box and transport it back to the classroom. I seem to remember getting my fair share of such opportunities.
While I can't recall for absolute certain if I carried the box differently at first, I do remember feeling quite the adept young fellow by carrying it slung against my hip with only one hand on the box. Yes, I was quite proud of myself, and, fortunately, pride did not go before a fall.
I'm not sure in what year I began to perform this chore or when it stopped. May it possibly have continued from about grade three to seven (which was when elementary school finished in Montreal in those days)? In my mind, however, I am in grade five and in Miss McDonald's class, the lovable Miss McDonald.