Did your dad ever mention what kind of soap he used back then? Because Dawn has degreasers in it that strip wax and oils right off, so even on old single stage paint he was probably just speeding up the fade. My mom used to tell me to use a bit of kerosene on bug splatter, which is fine if you enjoy bare metal showing up in a year. The one that got me was her saying to scrub bird poop off with a dry rag, and now I have little swirl marks shaped like regret.

Found the same thing on mine after a decade of leaning it against walls and using it as a straight edge. Still use my phone calculator for everything, just out of stubborn habit.

Did you end up with any permanent marks on the concrete from the big machine? Tbh I had a similar learning curve when I borrowed a buddy's gas unit and it left those little pockmarks all over my sidewalk. It sucks to realize you were overdoing it the whole time, but good on you for finding a setup that actually works.