Google copper and metal fume fever. Most of the info on metal fume
fever refers to galvanized materials (zinc) but I did find info
saying that a lot of copper fumes could do the same thing.
I spent about 7 months welding silica bronze, which is 99% copper. I
didn't notice any more brain fog than I usually have, but I did
notice my allergies going wacko. I was getting super sensitive to all
of my usual allergens. I suddenly got smart and started wearing a
disposable 3M respirator designed for welding fumes. That really made
a big difference.
Those were clearly fumes. I do not know how much of an impact jewelry
scale copperwork would make on your system.
In general my brain fog has to do with all of the multitasking that
most women do when dealing with children, husband, home, income, and
the numerous demands people think they can make of self-employed