I scrubbed everything out with a sponge and lots and lots of water after using that product. I also did a vinegar cleaning run of 2 gallons 50% water 50% vinegar.
After that I again Watch thoroughly with water and scrub with a scrubber sponge.
I will try to do a sacraficial run with some cheap vodka diluted to see if it comes out clean or blue.
According to Wikipedia: Verdigris is the common name for a green pigment obtained through the application of acetic acid to copper plates or the natural patina formed when copper, brass or bronze is weathered and exposed to air or seawater over time.
It could be that the acetic acid in your must and backset is what caused the blue you see.
I've never tried to use vinegar, (acetic acid), to clean off verdigris. I've, also, never left the backset in the still for 24 hours. It kills weeds much better when it's hot, even if you are tired, it's the early hours of the morning and you have to work tomorrow.
Citric acid cleans up verdigris in minutes in my experience.
I don't like putting spirit runs through bright copper, so have always avoided doing that. I've read a few posts by members who have and didn't like the results. Stripping runs usually break in my new copper before the spirit run. If I ever do get caught out, I run some feints and return them to my feints collection.
After a lots of cleaning and a sacrificial run I'm going to have a go at a final Spirit Run of this funky blue stuff.
I really hope it clears up because I'll lose all the play ever doing it a third time. I've got about 35 jars for a 4 gallon run. Hoping to do lots of small cuts. Updates to follow soon