This cup is made of pure copper which has a tendency to darken, this is due to natural oxidisation. It is essential to clean inside the cup prior to use.

Squeeze the juice of a whole lemon into the cup, add one tablespoon of salt stir and fill with warm water. Allow to stand until the oxidisation has gone, using a brush will speed up this procedure. The exterior of the cup can be cleaned by rubbing the surface with half a lemon dipped in salt.

The cup should be washed before use. Repeat regularly to prevent the formation of verdigris.