Copper hydroxide formation??

[cwrwfawr]

I chucked a campden tablet into my mash tun (picnic cooler box) and when I looked today the copper manifold had a blue resisue all over it, I think it may be copper hydroxide. Any chemists out there have any ideas/advice if I'm right & if it's poisonous?

[cwrwfawr]

Ok, have consulted John Palmer and am assuming it's just verdigris, which can cause copper poisoning but can be cleaned off with vinegar.

[koomber]

Don't use camden tablets where there will be long term contact with metal. It can corrode any metal parts.

EDIT: What you've probably got is copper sulfate. Comes from the copper reacting with the sulfate from the camden tablet. It should come off with some vinegar.