Wash and drain the sour cherries. Core approx. 4-5 cherries and crush the stones (preferably in a freezer bag). Layer the kernels with the cherries, rock candy, cinnamon, orange peel and cloves in a large or two small glasses (the rock candy on top). Pour the double grain over it, close tightly and let it steep for about 5-7 weeks in a cool, dark place. Shake a little more often. Filter the liqueur and fill it in bottles.