A method of producing settable, strong, rigid, durable and machinable compositions including plastics and organic fibres including the steps of: (a) forming a polyolefin source of plastic into particle sizes about 2 mm to 10 mm in diameter; (b) forming a polystyrene source of plastic into particle about 2 mm to 10 mm in diameter; (c) forming a natural organic fibre source into fibres in a size ranges between 0.2 mm and 5 mm; (d) mixing the above in a ratio between 70% to 20% by weight of a), 60% to 20% by weight of b), and 50% to 10% by weight of c) to form a combination until the combination is substantially mixed; (e) drying the combination of d) at a temperature up to 135.degree. C. until the mixture is stable dry; and (f) mixing and drying the combination of e) thermally and/or mechanically to achieve a moisture content below 1% for the combination.