The Stovebolt Site Forums The Shop Area The Electrical Bay What are Starter Brushes made of?

So, I rebuilt my starter over the weekend, and I was wondering what the brushes were made of. I had always figured that they would be made of carbon, or graphite or such, but they really look coppery, and feel metallic. I'm sure they aren't copper, are they some kind of compressed mixture?

Thanks all.