A method of making a finished product includes the steps of providing a feedstock comprising a polymer component comprising 5 to 100 parts by weight of a polymer selected from the group consisting of polyethylene in particulate form, polyvinyl chloride in particulate form, and a mixture of polyethylene and polyvinyl chloride both in particulate form; 0 to 95 parts by weight of polystyrene in particulate form; an extender, and optionally reinforcing fibres or particles; mixing the feedstock with a thermosetting resin selected from an unsaturated polyester resin in liquid form and a catalyst for the polyester resin and an epoxy resin in liquid form and a catalyst for the epoxy resin; and subjecting the product to suitable conditions of temperature and pressure to cause the polyethylene and/or the polyvinyl chloride and the polystyrene, if present, to melt and the thermosetting resin to set to form the finished product, e.g a shutter board.