Question

Why do copper objects lose their lustre after sometime?

Answer 1

because it reacts with oxygen and then due to corrosion it layer remove and it loss its shine

Answer 2

Heya mate,

Copper ornaments and objects lose their Lustre after some time due to corrosion that is when the metals come in contact with air and moisture n hence its layers gets removed one by one and hence it loses its lustre.

HOPE THIS HELPS!!