Modeling tools have been used in leathercraft forever to create visual art using leather as the canvas.  These tools also happen to work incredibly well in the process of removing sneaker uppers from soles. For sneakers with a sole stitched to the upper, the stitching should be removed before attempting to separate the upper from the sole.  The smaller of the two spoons on the modeling tool is perfect for sliding beneath the thread, and the tool is sturdy enough to not flex or break while pulling out the stitch.   If you’re using a chemical method (e.g. acetone) or an indirect heat method (e.g. oven) to de-sole, the two sizes of pointed and curved spoons on the tool work much like a bone folder would in delaminating the shoe adhesive; but, with a higher degree of precision and control.   If you’re using a direct heat method (e.g. heat gun), as you move the heat along the sole, place the modeling tool spoon along the top edge of the sole and directly in the path of the heat.  This will heat the metal and make the spoon much more effective at delaminating the shoe adhesive and to gradually work down between the upper and sole.