From ATXHackerspace

One of my first attempts, using a fairly strong etchant

Second attempt, vinyl stickers cut out on the Cricut and stuck to the metal via transfer tape.

After spraying a heavy coat of transparent rustoleum spray paint, I removed the vinyl

While etching in a weak solution (1 T Copper Sulfate, 1 T salt)

As the etch progresses, bubbles bubble and blobs of metallic copper rise to the surface. the smell is kind of ... dusty.

The raw end result has a nice crystalline appearance in the black areas. I wire brushed the lower piece and sanded the high spots with a fine sanding sponge.