Compared to many other metals aluminium has good corrosion resistance. This is because aluminium develops a thin oxide layer on the surface when the metal comes in contact with oxygen. The oxide layer protects the aluminium against corrosion and if it is damaged, it will immediately regenerate, provided there is oxygen present.
If aluminium is stored in environments without major temperature fluctuations and not exposed to moisture, the oxide layer without further surface treatment will protect the metal against corrosion.
The video shows how aluminium can be damaged by water: