Raw brass oxidizes easily especially when it comes in contact with your skins natural oils and the outdoor elements. The good news is it is easy to take care of naturally! Take a piece of lemon and rub it on the oxidized area. Use a cloth or toothbrush to rub the lemon juice in and repeat if needed. Wipe with damp cloth to remove the lemon juice. To keep the natural brass finish longer use a dab of olive oil or Renaissance Wax polish and you will be in great shape!