This is a magic recipe! I am on a lot of medication and it doesn’t t take long before my silver jewellery becomes tarnished. So annoying! I tried your recipe after discarding a lot of others that did a part-cleaning job so I must admit I was a bit skeptical. To my delight everything I cleaned came out shining and sparkly. I’ve used it on gold, diamonds, emeralds, amethysts but would not use it on pearls.
You can’t use anything else instead of baking soda. None of the other ingredients are necessary either… It’s specifically the vinegar (acetic acid) and the baking soda (sodium bicarbonate) that react and cause the reaction and hence the bubbles. The water actually inactivates both significantly and the salt (sodium chloride) is totally inert in the presence of the acid and base. As a matter of fact, when you combine the acetic acid and sodium bicarb, you get water and salt. The foil also does nothing…you can use any dish.
Read Before You Start!: Gather your ingredients and line your pan with a sheet of foil (shiny side up). Lay out your dirty jewelry and have each part of the jewelry touch the foil. Not sure why this is important, but apparently it is. (Note: I cleaned my silver, 14k white gold and even a diamond ring without any problems. I don’t recommend using this cleaner on stones like opals and pearls. Not sure what the reaction would be to these types of natural stones.)
If the jewelry is very dirty or very tarnished – like silver or gold – then you may need to repeat the process so just add a little more baking soda and more boiling water – but make sure it’s boiling, that’s key!  You can also use a toothbrush to get in all the nooks and crannies of detailed jewelry. Be careful with precious gems, stones and metals.