Natural alum dipped in water rubbed lightly on the ringworm site night and day for 3 days. It stings a little at first. By the 3rd day, the area is dry, a little scaly and the skin may flake off. The skin area also darkens a bit but the colour returns to normal in a few days. 3 days - end of story! Although this treatment was started as soon as the ringworm was noticed.