It's an outdated view. 

The one that says not to mix metals. 

Not only can you, you should to add visual interest and depth to your space. 

Now, let's unpack a few tricks that will help you do so successfully and leave your space feeling professional decorated. 

TIP 1 - First, pick one dominant metal and another metal as an accent. 

TIP 2 - Be careful not to choose metals that are too similar in tone. It will look like a mistake. Contrast is key. 

TIP 3 - Separate metals by height. For example, use one metal for lighting and the other for cabinet hardware. 

TIP 4 - Consider using textures. Combine matte, polished and textured finishes to add visual interest.

And lastly...

TIP 5 - Keep it subtle. Your metals should never compete for attention.