Homemade brass cleaners are intended for unlacquered brass and use ingredients such as white vinegar, salt, lemon juice and baking soda. Lacquered brass usually only requires cleaning if it is heavily soiled, since the lacquer keeps it from tarnishing. In that case, dish washing liquid or mineral oil is advised.
A mixture of 2 parts white vinegar, 1/4 part salt and 2 parts water makes a homemade brass cleaner that works on pieces that are highly corroded. Bring the mixture to boil, and then soak the brass in the mixture while it's still bubbling. This method may harm embellishments on the brass pieces, such as paints or metallic leafing. After treatment, rinse with water and air dry.
Another option for heavily corroded, unlacquered brass is to make a paste of lemon juice and baking soda and then rub it onto the piece to clean away corrosion. Dipping a half lemon in salt and then rubbing it on the brass also works. In either case, rinse the piece well after treatment.
To polish the brass after cleaning, mix salt, white flour and white vinegar together, in equal amounts. Rub the resulting paste on the brass, and let it sit for an hour, then rinse and dry the piece. Buff the brass with a soft cloth to finish the job.