To address the dual problems of the depletion of natural resources and the environmental impact of a growing volume of wastes, effective recycling of various products and materials has become an important challenge. Especially, the amount of plastic waste is extremely large, and thus it is very important to establish effective process of recycling them as soon as possible. However, the mechanical properties and durability properties of the products made from waste plastics are believed to be inferior to those of products molded from virgin plastics, and thus their application area is presently limited. We had used pre-consumer polypropylene and checked the influences of molding conditions to the mechanical properties of the recycled polymer recently. And we found that the mechanical properties of pre-consumer polypropylene was very brittle compared to the virgin polypropylene at the usual molding condition. However, as increasing the molding time and/or changing the cooling condition, the mechanical properties of it increases very much. From the results, we can conclude that the major factor of the degradation of mechanical properties is not the irreproducible chemical deterioration but the reproducible physics deterioration caused by molding histories. And also we can improve the mechanical properties by the simple refinement of molding conditions. In this report, we used real wasted containers and package plastics and investigated the�@influence of molding conditions to the mechanical properties.