Eco-friendly stain for copper

To degrease copper before enameling and to remove scale after firing, copper must be pickled.

The ingredients for an eco-friendly stain are available in each household, just mix 250 ml of vinegar and 1 tablespoon of salt. The stain acts even better when it is heated. An old porcelain or glass bowl on a hotplate or on a tealight stove are very useful to do so.