Method of upgrading composite materials

The procedure consists of cooling the composition material to a temperature of between -40 and +10 deg C, and preferably between -30 and -10 deg C, and grinding the cooled material to dissociate fibrous materials such as felt, textile or non-woven material from non-fibrous plastics, which may be lubricated, plastified or filled. The fibres are then separated mechanically from the non-fibrous materials. The recuperated materials can be re-extruded, for example, to make rigid components used in the manufacture of motor vehicles.