u/FoxApprehensive6368

Hi-I have a Jiffy J2. It was given to me by a friend. It is not the first Jiffy steamer I have used, I am very familiar with the brand. None of the others ever had this issue. The steamer water turns blue. The copper tubing has oxidized and is turning the water bright blue.

I took the hose off. I took the copper pipe off and cleaned it. Reassembled. Then I put a little vinegar + distilled water in it and warmed it up. Poured it out. Rinsed and repeat with distilled water only. It did it again. I guess the vinegar is causing the copper to oxidize? And if so, how do I remove it and stop it from coming back? Any ideas? Thanks in advance!