Soil contaminated with motor oil and gasoline can be improved using bacterial solutions and microbial calcium carbonate precipitation. The researchers mixed sandy soil with the pollutants and tested different methods. They found that using bacterial solutions and cementation solution injection produced positive results. Gasoline had less inhibition compared to motor oil, making it easier to improve. Bacterial flocculation was effective in stabilizing soil contaminated with motor oil. Analysis techniques confirmed the success of these methods.