If you made your own balled headpins using fine silver wire, you can skip this tutorial. Fine silver, which is 99.9 percent pure silver, will not darken in the flame the way that sterling silver and copper will. This is because fire scale is caused by oxygen combining with the copper in metal when it oxidizes through exposure to high temperatures such as a flame from a torch.
Since sterling silver is 92.5 percent silver and 7.5 percent copper, the copper alloy in sterling silver oxidizes in the heated flame, producing a blackening effect on the surface of the metal. Some artists like this look and simply leave their darkened headpins as-is. Other artists deliberately heat-darken their metal for various creative effects.
If you wish to remove the fire scale from your headpins, there are a few approaches. For instance, you can try polishing them with a brass brush or with coarse steel wool or sandpaper, or with polishing brushes and buffs on a flex-shaft. Personally, I find this unnecessarily difficult and time-consuming. My preference is to use a simple “pickle” solution to remove fire scale from blackened metal.
Various pickle solutions are possible; I suggest using something that is very safe and non-toxic. I have used citric acid (which can be found in Mediterranean food stores and some grocery stores); it is very inexpensive and effective. Best of all, it's non-toxic so it can be used safely without any worries.
Another alternative is dry acid (sodium bisulfate), the type used to lower the pH in swimming pools and spas. You only need a teaspoon of dry acid and a medium-size bowl of hot (not boiling) water, and a plastic utensil to remove the wire pieces from the solution once they’re cleaned.
Heat water to almost boiling, and pour it into a glass or ceramic bowl. Add a spoonful of dry acid to the water and stir to dissolve it.
Safety tips: NEVER add water to acid, ALWAYS add acid to water.
Avoid hovering over the bowl of acid solution, as the fumes are not safe to inhale. For this reason, never use boiling water, just very hot water.
Work in a well-ventilated area.
Drop the headpins into the acid solution. If necessary, press the wire pieces down into the solution using a plastic utensil:Within a very short time, you will notice that the fire scale is removed from the wire. Silver turns very bright, almost white. Copper turns bright orange:
Remove the headpins from the acid solution using rubber gloves or a plastic utensil, and rinse them in water. Allow them to air dry, and they’re ready to use.
I hope you enjoyed this tutorial. Many more wire jewelry techniques and projects are found in my instructional DVDs and eBooks, including Arty Jewelry, Arty Jewelry II, Arty Jewelry III, and Arty Jewelry IV. I also offer day classes in jewelry stores in the Southern California area, and I teach my techniques during Wild Wire Women retreatsheld in my mountain home in Idyllwild, California.