I went on a 4 year hiatus from brewing. Question is I pulled out my counter flow cooler and discovered there was still some liquid in the CFC (it was not capped) I flushed it out and the liquid is pretty black. when I brewed in the past I used to store the CFC with PBW so Im sure the liquid was once PBW also the end of the coil is green from oxidation. I would like to salvage the cooler can anyone give me advice on how to clean the inside of the chiller. I was thinking I should recirc a vinegar solution with my March pump rinse then recirculate PBW and finish with a rinse. Does that sound like a good stratagy. Does PBW work better if it is moving or just as well if it is in static contact with the copper.