The video mentions an “activator” shaken not stirred (sorry, I just heard Sean Connery past) internally prior to submersion, however his post lists only 3 items needed;
1. H₃NSO₃ - Sulphamic Acid Mixture;
2. Sonax Ultra Cleaner;
3. Dishwasher salt;

I’m unsure if he used the Sonax to remove the paint daub at the start or if this is being used as the activator. The liquid poured into the tank is clear and I suspect just a small amount of the acid to wet out all surfaces, or to act as a pre-clean.

One final thing to consider, while his results appear outstanding, remember this is a 5 year old tank and I suspect the staining may be more related to coolant staining on the surface than outgassing of a 50 year old tank.

So the real question is who is going to step up and try this, complete with photos so we can dispel the myth or prove it’s worth?