After extracting the gallstones from the cattle’s intestines they have to be washed thoroughly with cold water to remove blood clots, impurities etc. After washing they are dried for two to three weeks in a dark and well ventilated environment at a temperature of approx. 20 degrees Celsius. The stones have to be moved regularly for better drying and to avoid them sticking at each other. After full drying the stones are packed in hermetically sealed bags.