What's This Green Residue in my Shank?

So I just bought a used, dual tap tower that is in pretty good shape. I removed the taps though and found inside the shanks some kind of green corrosion I think. It basically looks like a corroded penny but I don't think that there is any copper in it. I tried spraying with some cleaner and wiping and scrubbing it out with a little brush and most of it did come out but not all of it.

Then I ran about 5 gallons of BLC through it and that didn't get the rest of it.

The shank connects to some metal tubing that runs all the way down into my kegerator where it then connects to my clear tubing. I'm worried that the corrosion (or whatever it is) is down in the metal tubing too.

Anyone know what this is and how I can get rid of it?

Pictures to come

I know the pictures aren't great but you can definitely see what is going on inside.





Thanks for any help you can give.

Yeah, it does look like copper corrosion.

Try some white vinegar, maybe?

The brass is wearing and corroding. It comes from copper oxide released from the brass.

Green stuff in your shank huh? Better get that looked at by a doctor, wouldn't want it to start leaking randomly...

its spelled skank not shank... and if your skank has green stuff time for a new one

Yikes! The last thing I want leaking from my shank or skank is green stuff.

I tried the salt and vinegar solution and it did get rid of the green corrosion, but now the inside is filled with orange rust.

I'm starting to think the few bucks on a couple tower shanks might not be such a bad idea.

More money upfront, but you will not have this issue if you buy Stainless as a replacement. Whenever I tear down my Perlick faucets and SS shanks they look almost like the day they were installed. My old brass ones looked like crap after 6 months of use.

That's probably what I'll do. I have a leftover SS tower shank from my single tap so I'll probably just use that and buy another.

Yep, it's copper oxide from the brass. Try some CLR or a wire pipe cleaner if you can get one to fit.