Over time even the most faceted gemstone can lose a little sparkle with a buildup of oils and grime. Even taking a shower can cloud your ring. The products you use, like your shampoo, conditioner, or body wash, can cause build-up on your gemstones. It is best to take them off before you shower.
The safest way to clean gemstone jewelry is to soak in warm (not hot), water with a mild liquid detergent (Palmolive or Dawn are good choices) and then gently clean with a soft brush. A child's toothbrush with very soft bristles is recommended and don't use one that was previously used on teeth. If there is any trace of toothpaste it could scratch your jewelry because of its abrasive ingredients. Dry with a soft cloth.
Do not use this method on soft porous gems like amber, coral, emeralds, pearls or turquoise as the detergent can harm the stones.