Use the Scotch Brite scrubbing pad to gently buff the surface (Scotch Brite is a popular brand of of plastic scrubbing pad meant to emulate steel ... Ferric Chloride is another common etching ...

He’s come up with a way of creating PCBs with any 3D printer and steel rod ... is using the traditional method of etching away copper, just some ferric chloride and a bit of time.

The most common etching systems are based on alkaline ammonia and cupric chloride. Other systems include peroxide-sulfuric acid, persulfates, and ferric chloride. Process steps include resist ...