Yes, a good full shed with take off any stuck shed from the previous shed with it. It's taking off the outermost layer of skin cells, which is where the old shed is attached. It's like if you take off a set of clothes with dirt on them, the dirt goes with the shirt. If it had say a bunch of mud encrusted on it, it might start being a bit more difficult to remove, but the mud would still come of with the shirt - in this analogy being similar to if the snake had a bunch of layers of old shed in a spot, it gets tricky for them to peel off. But just a simple small bit is usually not any harder than normal.