1970s. It was the mid-1970s for me. Schools had introduced teeth brushing after recess to improve our oral hygiene. All of us had to fill a tumbler with water and then line along a drain to brush our teeth with the given toothbrush, rinse our mouths from the tumblers and spit it all in the drain! (Memory collected at the Woodlands Regional Library during the "The Singapore Story: My Heart, My Hope, My Home" campaign from 6 Sep to 31 Dec 2012)