A method of making plastic materials, such as plastic lumber, wherein recyclable plastics are sorted into at least two categories and the recyclable plastics in each category are then shredded and chipped, extruded, and mixed with selected colour concentrates to produce the plastic materials of a selected colour. This invention allows for the control of the selected colour to enable replication of such colour of the plastic materials, regardless of any variation in colour of the recycled plastics in each category.
