I don't really know chemistry, but some chemical reaction happened when I tried to clean a faucet, and I need help in understanding what happened.
I have a used faucet that looked like this(attached file). I decided to clean it a bit. So I put some citric acid powder on it and some hot water. I tried to clean it like I clean the electric kettle, but maybe I should have thought better about this. The thing started bubbling. After a couple of minutes I poured the water out. The water was greenish, and the inside of the faucet got covered with red residue. Now I wonder what happened here. Did I damage it? Did I clean it? What is the red residue and is it safe to use for drinking water? I have no idea what the faucet is made of, but from the color of what happed I here, I guess it is something with copper. Did the acid damage the copper in the alloy? Did it just clean the copper oxide? Is it now less safe to use for drinking water than before, more safe, or the same?