I have my C85 torn down for a complete descaling using a citric acid solution. I have a question about what to use on the group head. Since the group head is chrome plated, I wondered if using citric acid would be a good idea. If there were any pin holes in the plating, acid might get under the plating and cause it to start peeling. What would be a good thing to use, maybe one of the alkaline cleaners used for coffee pot cleaners?