This study examines the removal efficiency of lead from contaminated shooting range soils by different citric acid concentrations modified with potassium chloride. Concentrations of 0.01, 0.1 and 0.5 M citric acid were subjected to sequential single-batch washing experiment on 3, 6, 9, 12, 15 and 18% soil pulp density for 2, 4, 6, 8 and 10 h. Furthermore, 1 and 2 M potassium chloride-modified 0.01 M citric acid was subjected to similar washing experiment. The optimum washing conditions for the single-batch washing experiment were found to be 3% soil pulp density at 4 h. Under these conditions, lead removal efficiency was 25.1 ± 1.1, 80.9 ± 1.9 and 90.3 ± 2.6% for 0.01, 0.1 and 0.5 M citric acid solutions, respectively. Modification of low efficient 0.01 M citric acid solution using 1 and 2 M potassium chloride increases removal efficiency of lead by about a factor of two. Using 0.01 M citric acid mixed with 1 M potassium chloride, 77.6 ± 3.4% of lead was removed and 69.8 ± 1.9% by 0.01 M citric acid mixed with 2 M potassium chloride. Single-batch washing using potassium chloride-modified 0.01 M citric acid solution enhanced lead extraction from contaminated soils. Thus, low concentration biodegradable 0.01 M citric acid modified with potassium chloride is ecologically ideal for soil washing with little or no environmental concerns.