The letter charm on this necklace is made from raw brass. Raw brass will darken and patina naturally, which is normal and creates a lovely vintagey look but if you prefer to keep the charm brighter in colour it can be easily cleaned with a metal brass cleaner like Brasso (avoid contact with the gold plated chain). To keep your jewellery looking it's best, store in a dry environment in a little grip bag or an air tight box when not wearing it and avoid contact with liquids, perfumes, lotions etc