I don't have any copper pots, but vinegar is my go-to cleaner around the house. Try adding about 5 to 10 percent by volume to a fully flooded pot and let it soa

I don't have any copper pots, but vinegar is my go-to cleaner around the house. Try adding about 5 to 10 percent by volume to a fully flooded pot and let it soak for an hour or two, bring to a boil of you are impatient. This works wonders for my pots, shower, sink, etc.