Some jewelry just calls out for a patina. If you'd like to give your silver jewelry an aged hue without using harsh chemicals, consider using hard-boiled eggs. The sulfur in the yolk of eggs reacts chemically with sterling silver and can make it look aged.
Fill the saucepan about half-way full with water. Add a few teaspoons of salt to the water, then drop in the eggs. For an average-sized single piece of jewelry, two eggs will be enough, but the larger the item, the more eggs you need. Similarly, if you plan to oxidize multiple pieces of jewelry, you will need to add more eggs. Bring the water to a boil, and let the eggs boil for 25 to 30 minutes.
Place the eggs in a plastic bag or other container with an air-tight lid while they are still hot. Mash the eggs with a fork. There is no need to remove the shells, because you will not eat the eggs later. Be sure that the yolks are well-mashed, because the yolk is the primary source of sulfur.
Place the jewelry in the bag or container with the eggs, taking care so that the jewelry doesn't touch the eggs. You want the fumes from the eggs to coat the jewelry, but cleanup will be easier if you do not have to remove eggs from the jewelry later. Set aside. The sulfur in the egg yolk will react with the sterling silver and create an antique look. The longer you leave the jewelry in the container, the deeper the color will turn.
Check the jewelry periodically as it oxidizes to determine when your piece has achieved the color you want. Your jewelry will start turning golden brown and then go through a rainbow of colors until it gradually turns black.
To be sure the color on the jewelry is even, turn the entire container over from time to time so that the underside of the piece of jewelry gets exposed to the sulfur as well. Remember, although cleanup will be easier if you do not egg your jewelry, it really does not matter if the egg gets on your piece; it can be cleaned off. Expect to wait at least 20-30 minutes to achieve a nice patina, but you can leave the jewelry overnight or all day if you are sure you want a very black patina.
Remove the jewelry from the sealed container when it has become the color you prefer, then rinse it with water. You are done, unless you want to selectively remove some of the oxidized finish with steel wool to bring out highlights in the jewelry.
Color will appear faster when the egg is warm, but you do not need to begin the process when the egg is warm for the egg to oxidize sterling silver. The heat hastens the oxidation process.
To prevent getting egg on your jewelry, you can hang a string or wire across the top of the Tupperware or a similar sealed container and suspend your jewelry from it. You can also place your jewelry on a stand above the egg mixture.