I should have added, the cleaner I tried did remove a lot of the three year crud. It sprays on, wiped with one microfiber towel, finished off wiping with a second towel (as per the directions) The first towel really showed that a lot of dirt/crud was removed, but I could see a few oil spots that it did not completely remove. Something like
this is the only power buffer I have. I used it for RV's that have almost all flat surfaces. Autos I have always done by hand