NOVELTY - An insecticidal cleansing emulsion system comprises clear oil-in-water (o/w) emulsion in which oil phase contains anionic surfactant containing alkyl sulfate and alkyl ether sulfate, and insecticide is suspended as nanoparticles in water phase. Water phase contains cationic polymer or surfactant and metal salt, where upon dilution with water, anionic surfactant and cationic polymer or surfactant form a water-insoluble complex, and insecticide nanoparticles precipitate out of the water phase together with the water-insoluble complex.    USE - An insecticidal cleansing emulsion system for pet (claimed).    ADVANTAGE - The insecticidal cleansing emulsion system consists of insecticide having enhanced efficacy and safety, longer duration of insecticidal activity, and reduced loss of insecticide washed away, as well as amount of insecticide contacting humans and clothing. Lower amount of insecticide can be administered to control insect infestation that is otherwise possible using spot-on topical formulations, making it more environment-friendly.    DETAILED DESCRIPTION - An insecticidal cleansing emulsion system comprises clear oil-in-water (o/w) emulsion in which oil phase contains anionic surfactant containing alkyl sulfate and alkyl ether sulfate, and insecticide is suspended as nanoparticles in water phase. Water phase contains cationic polymer or surfactant and metal salt selected from lithium chloride (LiCl), sodium chloride (NaCl), calcium chloride (CaCl2), magnesium chloride (MgCl2), magnesium sulfate (MgSO4), sodium acetate (NaOAc), potassium chloride (KCl), potassium hydroxide (KOH), potassium acetate (KOAc), disodium phosphate (Na2HPO4), and/or monosodium phosphate (NaH2PO4), where upon dilution with water, anionic surfactant and cationic polymer or surfactant form a water-insoluble complex, and insecticide nanoparticles precipitate out of the water phase together with the water-insoluble complex. An INDEPENDENT CLAIM is included for eradication of insects on a pet which involves administering insecticidal cleansing emulsion system to a pet in which upon dilution with water, the anionic surfactant and the cationic polymer form a water-insoluble complex to eradicate insects on the pet.    DESCRIPTION OF DRAWING(S) - The drawing shows a bar graph indicating the efficacy of a cleansing emulsion system at 40 mg/kg compared to a spot-on formulation 225 mg/kg.