Premium Quality：After a long time in the humid air, the copper surface will form a layer of patina slowly, this is oxidation. So your bracelet turns green, it's normal and proves that the bracelet is made of pure copper.Tips:Our Copper Bracelets were coated. The best way to check if a copper bracelet is made of pure copper is to cut the bracelet and check inside is copper color.Suggestion: You take it off when you are swimming, taking a shower, or sweating for a long time, and avoid the bracelet becoming green due to prolonged exposure to seawater, sweat, or salt water.How To Clean The Magnetic Copper Bracelet?1. The green deposits on the skin can be easily washed off with soap and water.2. Soak the bracelet in a mix of water lemon juice or vinegar. rinse the bracelet with warm water and dry it thoroughly with a soft cloth. 3. Apply tomato ketchup on the bracelet. rinse with warm water and dry thoroughly with a soft cloth.Warning!! Do not use this product if you have a pacemaker, defibrillator, insulin pump, or any other implantable electronic medical device, or if you are pregnant.