Shiny or dull side of aluminium foil: Which side should face up when cooking, baking or wrapping food?

Aluminium foil exhibits two unique surfaces as a result of the production technique that rolls two sheets simultaneously. The shiny side is created from polished steel rollers, while the dull side interacts with another sheet. For general usage, both surfaces are interchangeable for cooking or preservation. However, with non-stick foil, it's crucial to use the coated dull side for food.