Lead loses its lustre due to:

The corrosion of the lead surface is responsible for it losing its lustre.

The metals lose their shine on brightness on keeping in the air for a long time due to the formation of a thin layer of oxide, carbonate or sulphide on their surface by the slow action of various gases present in the air.

• Sodium loses its lustre on exposure to air due to formation of Na₂O, NaOH and Na₂CO₃Sodium on exposure to air catches the O₂,H₂O(vapour) and CO₂ and forms Na₂O, NaOH