Two pieces of blue flint glass cullet
Two pieces of blue flint glass cullet, 1968. Cullet is broken and scrap glass which is added to the melting furnace containing the raw materials used for making glass. It is a way of recycling scrap and speeding up the process of glass-making as cullet melts more quickly than new ingredients and therefore saves fuel. Cullet may be the only ingredient in the batch, but generally constitutes only 20-25% of the ingredients.