I picked up six sticks of 1" galvanized schedule 40, been used above the water table in a water pump for 10 years. The outside isn't rusty, but the inside has a brown scale that I don't believe is rust - I think it's groundwater scale. Is there any realistic way I can descale this pipe to use it for a shop air piping system?
I was thinking of capping the pipes at one end and putting the capped ends downhill in my driveway, and filling the pipes from the top with some solution. But living most all my life in or very near Seattle, with it's perfect soft water, I don't know much about descaling chemicals. I'd like something cheap, of course.