Reagent: Dissolve 10 gram of KOH in 1 liter of distilled or de-ionized water (1% KOH solution).
Basic titration : In a smaller beaker, dissolve 1 ml of used cooking oil in 10 ml of pure isopropyl alcohol. Warm the beaker gently by standing it in hot water, stir until all the oil dissolves in the alcohol and the mixture turns clear. Add 2 drops of phenolphthalein solution to get end point.