The soil reinforcing procedure is a technique utilized to improve some soil’s engineering properties. In this study, a laboratory test is improved for re-using liquid filling packaging waste made of Polyethylene Terephthalate (PET) for reinforcing a specific type of sandy soil in Baghdad province in Iraq. These types of plastic waste are chosen due to the recent increase in their quantity in Iraq for their multiple uses, which led to becoming an urgent environmental issue that must be disposed of by re-using it in several areas, including soil reinforcement. The plastic waste utilized in the presented work is prepared in strips to form with different dimensions ranging from 20 to 60 mm in length and width of 20 mm. In addition, the plastic strip mixture is added to the sandy soil sample used in this study at a weight rate of 0.5% of the weight of the used sample. The outcomes of laboratory experiments are represented by direct shear tests and bench-scape plate loading tests. The results revealed an improvement of the soil sample through some laboratory tests, indicating that this substance’s inclusion in the selected sandy soil sample effectively reinforces this type of soil in the Baghdad governorate.