My cabinets are stocked with about a million different cleaners, for various household tasks. I don't even want to think about how toxic they all are! So when I needed to polish a brass holiday ornament, I wasn't eager to go out and buy yet another cleaner. Instead, I dusted off some high school chemistry skills and headed to the refrigerator.
In a cup or on a plate, mix some ketchup with salt. There are no special measurements. Your goal is to make a thin paste with some abrasive qualities. Please note that the salt can slightly scratch your brass, so use it sparingly.
With a soft cloth, apply the mixture to the brass and scrub. For tougher tarnish or to work it into intricate designs, you can apply the paste liberally and let it sit overnight. Wash the mixture off and see how your brass shines.