Many brass doorknobs, hooks and decorative objects have been lacquered to keep the brass shiny and to prevent tarnishing and darkening. If you want an antique look for your brass object, the lacquer must first be removed before treating the object with a chemical that will speed up the natural darkening process. The process is not complicated, but requires a well-ventilated area. This process also works well for darkening new brass screws and nails needed to hang an antique brass hook or light.
Dip a cotton ball in the paint remover and gently rub the brass to remove the lacquer. Repeat until all lacquer has been removed leaving a dull finish.
Pour 1/2 cup of ammonia into a ceramic bowl. Carefully place the bowl in the zip-close bag.
Insert the brass object in the bag next to the bowl of ammonia. Zip up the bag and allow it to remain closed for 24 hours.
Remove the newly darkened brass object.