Final answer:
Foil is used to protect loose soufflé cups from melting.
Step-by-step explanation:
Foil is used to hold loose soufflé cups to protect them and keep them from melting. The foil acts as a barrier that helps maintain the temperature and prevent heat from escaping, thereby preserving the shape and structure of the soufflé cups. It also adds a layer of insulation that protects the cups from melting due to external heat sources. For example, if the soufflé cups were placed in a hot oven, the foil would help shield them from direct heat, preventing them from melting.