The teacher on playground duty would distribute straws through which we sooked the milk. Some of the older boys - who I thought were rougher, tougher boys - would drink it direct from the bottle without the use of the straw. This naughtiness was very worrying for me because although I knew our teachers frowned upon such behaviour I was secretly impressed by it.
Every morning one of the boys brought to school an old empty babies' dried milk can to which he attached, through two small holes he had punched near the rim, a long loop of string. He would ask those kids - and they were, as I remember, usually girls - who had not drunk all their milk to pour the remains into his can. When it was about a half full of milk, he began to swing it around rather in the way a hammer thrower swings the hammer before he releases it. Not a drop of milk was ever spilled from the can as it rotated around him and got up to such a speed that it could only be seen as a blur like an aeroplane propellor. Later I discovered the science going on was centrifugal force. Yet, it is the magic of unspilt milk which makes me wistful, and is at the core of me, not the science.