Not sure if this is common knowledge , but thought I'd share it. Working on my Kentucky rifle kit and wanted to blacking/patina the brass hardware. Most people will use BC Brass Black and it looks to work as intended. I have used and use BC Super Blue cold bluing solution. I scuff the brass with 320 grit or a scotch brite pad, clean with acetone, alcohol, etc. and apply with a q-tip or cotton ball. It turns a dull even black in about 30-45 sec. Rinse in cold water and pat dry with a clean cloth. I apply a coat of Johnson's paste wax to protect the finish. The best part is most of us probably have a bottle of cold blue already, if not it can be bought locally about everywhere, unlike brass black .