This tool is extremely valuable to correct flaws in an image from dust and scratches and is a necessity for restoring damaged photos. Cloning also fixes visual garbage. The subject of this photo is the young boy. At the best shooting angle, there were distractions that could not be moved. The cloning tool can remove the problems to better reveal the subject.
Soft edges make the cloning blend better.
Hard-edges work well when you are trying to fix an area close to a sharp edge on your subject. Magnify your image on the screen so you can see details more clearly. Sometimes a very little change in location one way or another will make a big difference in how well the cloning works. Try both continuous and spot methods of cloning. With the spot method, you move the tool first, then make the clone, one spot at a time.