Ketones (acetone, MEK, etc.) will loosen grime very well & very rapidly, and are excellent at doing so. But their evaporation rate is so fast, that you often leave the dirt and grime on the surface. Loosened, but still there.

Naphtha isn’t as good at loosening grime as a ketone is, but the naphtha, with it’s slower evaporation rate, will finish the "washing away" part of the process.