Toothpaste is less problematic when it comes to cleaning jewelry. Just apply the toothpaste (preferably with a whitener) to a brush, and rub it on the piece of jewelry. Rinse well with cold water, Dry with soft cloth. This method can be used on different forms of fashion jewelry, such as bracelets.
Mix together one drop each of baby shampoo and water (regular jewelry cleaners, usually meant for the real deal, are too harsh to use on costume pieces). Use a soft toothbrush or Q-Tip to clean hard-to-reach spots. Rinse off quickly in cool water and dry with a clean, soft hand towel or microfiber cloth. Use a hairdryer on the cool setting to be sure each piece is totally dry. This will keep them from rusting. Use a warmer setting and the piece may warp, or the glue holding any gemstones in place could melt.