Hmmmmm, I'm old enough to remember milk delivered to your door and that went out in the early 60s. I think it was 1964 or 1965 when door to door delivery stopped in my area. I have about 7 or so of the milk boxes used to keep milk on the steps all from the local dairy here. My wife uses a few for decorating around the house, proch, and garden. We collect items from the local creamery/dairy...bottles, advertising items, photos, milk boxes, etc. Tales, if you really want a milk box, I have a small 'Dolly Madison Dairy' (stenciled) box that I was going to sell. I can send pics if you want.
I also remember 'churning' butter in school (kindergarten or 1st) in a jar and then spreading the fresh butter on graham crackers and eating it. I do not remember much else from those days but I do remember that. It was the only time I churned butter. I have an old Dazey churn but I do not think I would ever use it for more than a decoration. My concerns would be the same as yours.