If your jewelry is looking less than lustrous, there are lots of homemade options for bringing back the brightness. NOTE: Most of these options are best for hard gemstones set in silver or gold and are probably NOT a good choice for costume jewelry (vigorous cleaning could spell disaster for the finish) or any jewelry that contains pearls or soft stones like opals, turquiose, etc.
Lots of people swear by this one: combine 1 cup of hot water with one tablespoon each of baking soda, salt, and dish detergent. Soak jewelry for a few minutes; scrub gently with soft toothbrush if necessary. Rinse well and dry with a soft cloth.
For copper or brass items: head for the pantry. You can scrub copper items gently with ketchup, or soak copper items in lemon juice. For brass. try removing tarnish by rubbing with ketchup or a paste of salt, flour, and vinegar. You can also coat a dirty brass item with Worcestershire sauce and let it sit for a couple minutes. Use a soft cloth to gently rub away stubborn tarnish and finish by Rinsing thoroughly in clear water – if you don’t the item will have a sticky residue. Buff dry to avoid spotting.
Drop an effervescent denture tablet into a small bowl of warm water and soak jewelry in the fizzy mixture. Rinse in clear water.
Soak jewelry in a mixture of equal parts ammonia and hydrogen peroxide. Scrub if necessary, rinse and dry.
Soak jewelry in a mixture of 2 tablespoons of baking soda in a cup of white vinegar.
Line a small bowl with aluminum foil. Add a teaspoon each of salt and baking soda, a teaspoon of dishwashing detergent, and a cup of hot water. When the mixture fizzes drop in your jewelry and let it soak for about 10 minutes. Remove the jewelry and scrub lightly with a soft toothbrush. (NOTE: the aluminum foil is important in this method – the chemical reaction it creates when it comes in contact with the other ingredients helps clean metal).
Line a baking pan with aluminum foil (shiny side up). Lay out your jewelry in the lined pan. In a separate bowl combine a tablespoon each of salt and baking soda and a cup of boiling water. Pour the mixture into the pan, then slowly add one half cup of vinegar. It will bubble like mad. Let sit for about 10 minutes, remove the now-shiny jewelry, rinse in water, and dry
Stir 2 tablespoons of ammonia into one cup of warm (not hot) water. Soak jewelry for a few minutes, then rinse in clear water and dry.