So I recently rebuilt my pot still. Long story short I used a brass fitting to attach my pot to the condenser. It is listed as "lead free" on the packaging... and from my understanding all brass fittings in the USA are lead free. I did a vinegar run found a tiny leak around this brass/copper interface. As the vapor condensed... it had the slightest blue tint. The distillate at the other end of the worm was clear. Now the pot is new, the worm is not. I cleaned it before I put it away about 1 month ago (vinegar then water). I assume this is some copper sulfate residue in the proximal part of the worm as it joins the pot.... but I just want to be sure it isn't the brass. Everything I have read suggests it is not, but paranoia saves lives here...