Yes, Blue Goop works. I used it for a while after a friend gave me a jug of it. It was a blue colored liquid. But the name came from the look of the goop that came out of the barrel when removing it after letting it set and work for a while.
The guy who invented it was Phil Sauer. We were friends for years as he was an avid benchrest competitor and experimenter. We both belonged to the Washtenaw Sportsman's Club where I ran the cast bullet matches. He was an electrical engineer by trade but also understood chemistry. He invented blue goop and it became a huge success in the jacketed bullet ( lead bullets wearing copper condoms) benchrest world. It was cheap to make and worked well. It did not damage barrels as was evidenced by my observations of the bore condition with my Hawkeye borescope. Many forlks said that it would etch a barrel surface but had no proof other than conjecture. Old wives tales were what they were. If you use it properly, it won't hurt the barrel just as Shooters Choice does not hurt barrels now.
I didn't have a borescope early on when shooting cast bullet benchrest and used to take my barrels over to Phil's house and he let me use his borescope to look at the throat erosion and barrel wear. He was amazed when he looked in my barrel that had 3500 rounds of cast through it and showed very little throat erosion. A jacketed bullet barrel would have been a lot more eroded than a cast bullet barrel with the same number of rounds through it.
Phil won the national two gun NBRSA or IBS championship one year. He was a great source of information and I used to ask him lots of questions which he was always willing to answer. Sadly, we lost him a about 10 years ago and he is missed by everyone who knew and respected him.