The dipping method for removing tarnish from brass pieces requires that the brass piece is dipped in an ammonia mixture for about 10 minutes. The ammonia can remove even thick layers of tarnish, leaving the brass bright, clean and ready for polish.
To use ammonia for the removal of tarnish, the brass piece must be 100 percent brass without any decals or other design pieces glued to the metal. The ammonia solution used for the dipping consists of 1 part ammonia mixed with 8 parts water. If working indoors, open all windows and doors to ventilate the room during the ammonia use.
After dipping the brass, the metal can be brightened by applying a layer of mineral oil to its surface using a clean, dry cloth to rub the mineral into the brass. The mineral oil also reduces the need for future polishing and the chances of building up additional tarnish. A second method for reducing future tarnish is to polish the brass with car wax. Follow the instructions on the car wax provided by the manufacturer to add a layer of protection to the brass. The waxed protection should last between four to six months before needing to be reapplied.