LcoyoteS

Sadly, my knowledge of chemistry is very limited, so I have no idea what the chemical reactions are. I tried adding ammonia to the vinegar because I came across a website that said people in the Middle Ages sometimes exposed copper to ammonia fumes in order to get a deep blue pigment. Oddly, one of my containers of the deep blue liquid seems to be staying that colour, but another one is, like you say, turning into the verdigris colour.

Do you use plain linseed oil or boiled linseed oil?

It was iron contamination, but I got some nice rust, which I used to acid stain a concrete pot I made. I am using copper pipe pieces now to get some nice verdigris crystals. I am also getting a lovely deep blue-coloured liquid from adding ammonia to the jar. It seems to be taking forever to form crystals from the vinegar and ammonia solution, though.

Thanks! I suspected as much...

I am trying this with copper dish scrubbers, but so far all it has yielded is rust-colored scum. Is this normal, or are the scrubbers not actually copper? They have been sitting in the vinegar for two days now.