A rhodium-coating or a rhodium-plating is added to silver jewelry to prevent it from tarnishing, and to preserve it longer. Rhodium is frequently used to coat "white-gold" to make is more durable. Rhodium is a highly reflective precious metal (currently more valuable than gold and platinum) and is used to plate white gold or silver. It is a very hard wearing metal and does not tarnish.
Never use any chemicals on your rhodium items. Never use toothpaste (toothpaste is for teeth!). Never brush with a toothbrush. Don't use polishing cloths that are intended for use on uncoated silver, or for gold jewelry. Don't place in an ultrasonic cleaner. Never use abrasives of any kind. Never use silver dips. Never use ammonia based products. If you have an antique or heirloom, don't clean it without consulting an expert on your item. Consult your jewelry professional for more cautions on your piece of jewelry. Wash makeup off with warm water before you rub it off (some makeup can contain oxides or sparkles that might cause rub marks on your jewelry).
If you have a ring, the rhodium may one day start wearing off where there is a lot of friction. Just wearing a ring for many years will do this. Working while wearing your ring will accelerate this process. This wear usually starts at the shank (the part of the ring that goes around the finger). It can also happen with bracelets, earrings, or necklaces. With "white gold" you'll be alerted by this process starting when parts of your ring turns "yellow” or looks scratched, nicked, or dull. With rhodium-plated silver, you'll notice the rhodium wearing off when the silver turns color (dark, or yellowish). Return the piece to your jeweler for examination. Only your trusted jewelry professional can partner with you to preserve your investment. Blitz suggests that at least once a year, you visit and have your items looked at by your personal jeweler. Jewelry with stones, beads, or ornaments: This is complicated. You never want to expose delicate stones to harsh environments. Check with your jewelry professional for their recommendation for your individual, unique piece of jewelry.