Abstract: A waste plastic material, e.g. hard plastic waste constituted of vinyl chloride, polyethylene, and foamed polystyrene, soft plastic waste, or other plastic waste containing metal fragments, is immersed in a vegetable or mineral oil heated to 110.degree. to 180.degree. C. for melting in to a saturation of the plastic waste, the proportion of the plastic waste added to the oil being sufficient to saturate the oil. The melted plastic material, in which quantities of the oil are entrapped is mixed with a given dose of a neutralizing agent, e.g. calcium hydroxide, at a temperature of 220.degree. to 300.degree. C. Then, the resultant mixture, in which a quantity of the oil is entrapped is shaped into a solid fuel product, or into a predetermined form disposable in a landfill.