Some folks will say to soak it in vodka. I say don't worry about that. Rinse the HELL outta it with hot water. Very hot water, let it dry and go with it. If it still tastes nasty. just simply dump the whole tank and use a new coil.
The color change is normal. I have a friend in here that let me try some if his juice that was clear and it's now almost black. It changed colors just because of time. Nothing more... Nothing to worry about...