How to gut a computer case?

Now I'm not talking about how to take it apart for the purpose of upgrading, I can do that. What I want to know is how to remove the metal plates inside ( y'know the ones that hold the HDD's). I pretty much want to hollow out the inside of the pc tower. Anyone have experience doing this? I'm having trouble figuring out which tool to use to remove these plates for they aren't held in by regular screws but what looks like a small chunk of metal with no threading.How to gut a computer case?
Those are called rivets. You can use a chisel and try to shear them off.

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