All metals are water-friendly & can be worn in water. However, moisture accelerates oxidation & makes it tarnish faster. So it is best to avoid excessive moisture 

Proper Storage: Store jewelry in pouch or jewelry box when not in use to slow down oxidation.

Cleaning: Easily restore shine using a specialized metal polish (such as "twinkle"  for brass & copper only ) or a gentle DIY method

Brass & copper: Equal parts of lemon juice & baking soda.

Silver: Baking soda & water

Gold/Gold-filled: Castile soap & water

Use soft cloth or soft toothbrush