To adjust metal color in C4D (Cinema 4D), you need to use the material editor. Open the material editor, select the shader you're using, and navigate to the color channels. For a metal look, you can use the 'Specular Color' for the highlight color and adjust the 'Reflectance' parameter to control the shininess. You can also add a noise map to create a realistic texture. Remember to adjust the 'Roughness' to simulate the roughness of the metal surface.