I have these great, ready-made silver-plated quick link rings from Beadalon, shown at the top of this photo. They're about the diameter of a quarter. They're really cool, but for my style they're just a tad too shiny, too perfectly formed. Others love these attributes, but I like more of a hand-crafted look in my work.
First I hammered them with a small rivet hammer, flipping them on my steel block to hammer both sides. Those rings are shown in the middle of this photo. They looked way better to me, but I still wanted more.
I decided to oxidize them. Using bowls designated for crafts only (with NOT FOR FOOD written on them in marker) I first mixed a neutralizing solution of baking soda and plain water in one bowl--about 2 tablespoons of soda to maybe a pint of water. Next I heated water in a glass bowl, and put in two drops of Patina Gel Liver of Sulfur. It's really stinky so open a window. I used tweezers to dunk the rings, watching them darken and removing them quickly right into the baking soda water to stop the reaction from getting too black. Then I rinsed them in plain water and dried them off. My oxidized quick links are the bottom rings in this photo. They totally look like fused silver rings that I made myself!
Cool, huh! Plus, the liver of sulfur solution degrades in a couple days and makes a great fertilizer. Just store it in a jar until it turns clear, then water your tomatoes!