Ammonium-based deep eutectic solvents as novel soil washing agent for lead removal

•Deep eutectic solvents (DESs) are used for the first time for soil remediation.•Saponins are used to enhance DESs performances for lead (Pb) removal.•Natural DESs formed with choline chloride and fructose/sucrose examined in details.•Up to 72% Pb was removed with a combination of 40% DES-fructose and 1% saponin.•Soil corrosion by DES washing is negligible.