Brian, I am curious as to how you will apply it.

I have considered a large basin to soak the radiator in
thinking that a soak will give it more time to work.

It seems pressure wash with the solution won't give it time to work.

And last, how to dispose of it ?

Down the gutter, or into the sewer through the house plumbing ?

Or... take it to the hazardous waste disposal site like I do paint and batteries ?

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80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250