Is there any difference between the two sides of an aluminium foil? (shiny/matte)
If so, when to use each one? For example, when covering something or when using as a pan cover to bake/cook something on top of it.
Appearance is the only difference! There is no performance differance between the shiney side and the dull side. Two sheets are run through the rollers in the mill to acheive the desired thickness then sized, separated, cut to length and packaged.