Fake silver and gold jewelry may contain a variety of metals, including iron. Metal jewelry that contains iron is prone to rust -- especially in the case of rings, which are likely to come in contact with moisture or sweat that oxidizes the iron. Drying off the metal ring after you wash your hands helps minimize rusting, but if rust does develop, you can remove it to help make the ring look new again.
Mix two parts baking soda or borax with one part lemon juice to form a paste, combining ingredients until it is as thick as toothpaste. Add baking soda if the paste is runny, or more lemon juice if it is too thick.
Smear the paste onto the ring. Coat the rusty areas with a thick covering of paste.
Allow the paste to dry completely. Rinse under clear water.
Cut a potato in half and dip the cut half into salt or baking soda. Scrub any remaining rust on the ring with the cut potato half and the abrasive salt or soda.
Commercial rust removers also break down the rust and may work well on plan metal rings. The rust remover can damage glass or plastic stones and other decorative items on the ring, since it does contain an acidic cleaner.
Coat the metal ring with clear fingernail polish to prevent rust in the future. The polish requires periodic reapplication as it wears off.