Soak the stainless jewelry in a bowl containing a mixture of mild soap and warm water and let it sit for a few minutes. Next, take a soft cloth and rub the jewelry. For hard-to-reach areas, like grooves or engravings, you can use a soft-bristled toothbrush that will ensure you reach those hard-to-get areas.
Keeping your brass or copper jewelry clean will prevent it from turning your skin colors. The color change occurs as a normal reaction to the prolonged brass or copper exposure to the skin, typically caused by oxidation. Wet your brass or copper jewelry piece with lemon juice or vinegar or baking soda, sprinkle with a bit of table salt then rub with either a soft cloth or your fingers until tarnish is gone. Rinse with water then dry thoroughly.
If you have a large brass or copper item and you want to clean it quickly, you can boil three cups of water, add a cup of vinegar or baking soda and one tablespoon or more of salt. Stir until the salt is dissolved and then place them in the water for 10 minutes. Once the time is up, rinse the pieces with lukewarm water, the tarnish will come right off.