LimiShine!
Great advice, DanW!
I put 1 tablespoon of LimiShine in a quart of hot water, added a few drops of dish washing soap, put the lid on it and shook the plastic container for about 10-15 minutes. Then I washed it in warm water until the wash water stopped showing soap bubbles. I covered the 450 brass casing with tap water, added a teaspoon of baking soda, and rolled the casings around for 2 or 3 minutes. Then I rinsed them with warm tap water for another minute, drained them, then covered them with distilled water and rolled them around for 2 or 3 minutes, drained them again, and put them on a tray in the oven at 170F until they were dry.
They were already pretty well cleaned with the vinegar and salt solution, but LimiShine made them all look even brighter and more uniform. Now, the brass color on all of them is identical. It even helped clean out some of the bases where the flash hole is that the Vinegar didn't get very well.
BTW, neither Vinegar or Ammonia solutions anneal Brass. That is a physical, not chemical, process that requires a movement of the domain structure of the Brass that only a temperature of 685F or higher can accomplish. Water boils at 212F.
Neither does the Chloride ion of a salt solution chemically react with the Zinc in the Brass. For Zinc to dissolve out of the Brass, or be chemically affected by an aqueous solution of Sodium Chloride, thus changing the domains of the Brass, the Zinc must be MORE reactive than the metal in solution. In this case, the metal in solution is Sodium, which is extremely reactive with water, and MUCH MORE so than Zinc. So Zinc will NEVER replace Sodium. In other words, you won't be observing Sodium metal platting out on your Brass. Even if it did, it would immediately react with the water to release Hydrogen gas, which is never observed.
The "other" metal in all aqueous solutions is H+, the Hydrogen ion. Even in a 1 Molar concentration, Vinegar produces a pH of only about 2.4. White Vinegar is typically 5.6% in strength. You can drink that and often do when you put Vinegar dressings on your salads. IF Zinc were reactive to that weak of an acid you would observe the formation of very small bubbles on the surface of the Brass, especially in warm or hot water, which would indicate the formation of Hydrogen gas. Such gas not only NOT observed, it is not possible from a Gibbs Free Energy calculation, which I won't go deeper into here except to say that if the GFE calculation is not positive then not only is the proposed reaction not possible, the reaction in the opposite direction will be naturally occurring, even if it may be extremely slow. (The GFE for the conversion of Diamond to graphite is positive, meaning that given enough time all Diamonds will naturally transform into graphite, but graphite will NEVER spontaneously transform into Diamond without a correspondingly greater increase in the Entropy of the graphite's surroundings caused by sudden increases in temperature or pressure deep inside a volcano, which is why diamonds are found deep in the risers of old, inactive volcanoes.)
Vinegar's chemical name is Acetic (or Ethanoic) Acid. In concentrated form it is called Glacial Acetic Acid because it forms crystals at 62F, which is just below room temperature, making it appear to be slushy. It is very potent and opening the lid on a jar of it releases fumes which cause immediate and severe discomfort, speaking from experience, which is why it is always used under a hood. Fumes from a bottle of glacial Acetic Acid are MUCH stronger than fumes from a bottle of White Vinegar found in stores.
When my ultrasonic cleaner comes I will be using LimiShine and soap in it. Thanks for the tip, DanW!
