For pickling (cleaning and brighten the soldered jewelry) take a 15 percent sulfuric acid. It can be mixed in the pharmacy. You can also use Vitrex which is a powder to be mixed with water. Both liquids work best when they are warm or hot.
You fill the liquid into a heatproof glas-bowl with a diameter of 10 to 15 cm. Put the heatproof glas-bowl on to a tea-warmer. Heat it up with a tea-light-candle. I am working with this method for nearly 30 years now.
Fill an old pot with water and put a jam jar(old glas jar) into it. In the jar should be the Vitrex or the 15 percent sulfuric acid. Heat the water up. It should be hot, but it mustnīt cook.
Take a plastic, copper or brass tweezers for putting the jewelry into the acid. You mustnīt use an iron or steel tweezers!
After pickling a jewelry it must be cleaned with water!
Children or other persons should not use the acid in any way!
If the acid contacts your hands, wash them immidiately!
Closures in jewelry are sometimes made of steel. They mustnīt be pickled!
You can find a filmclip and more information about pickling in tutorial 2!