To maintain a piece of jewellery for brilliance, a simple warm water ‘bath’ in your sink or in a small container with a splash of regular dish soap does the trick. A splash of windex in addition, and then use an old toothbrush to ‘scrub’ around the gemstones and the intricacy of the metal design.
You want to use a solution that has a slippery texture to it, so that the solution easily rinses off the metal and stones. A lot of times I hear people asking about using toothpaste, but because toothpaste is an abrasive compound that cakes onto metal or gemstones, it actually does more harm than good.
You need to be fully aware of what kind of gemstone/mixed media jewellery you are washing. Certain gemstones, like emerald, pearls and opals are not suitable to be washed with any chemical solution, but best washed under luke-warm water only.
The reason for not washing your jewellery under a running tap in an un-plugged sink is simply to keep any possible loose gemstones or decorative elements in your jewellery from coming out of their setting and going down the drain. Warm water expands precious metal in a minuscule way, but it can be enough to loosen up a micro-pave set stone enough to wiggle itself out of a setting; particularly if you are washing your ring in an ultra-sonic cleaner that you have purchased for cleaning jewellery at home, or if there is one that you are using at your work-place (dentist, medical offices).