While some bars lend themselves to cutting on a guitar, many require the use of knives, and different types of bars are best cut with different styles of knives. Some bars respond well to a serrated knife, while others require a sharp chef’s knife. Whatever is used, the goal is to cut straight, vertical sides and to leave corners that are square, not rounded. When cutting particularly soft centers, a brief period of refrigeration—approximately 5 minutes—firms the center enough to allow it to be cut cleanly.