Many "real men" in my area use "Lava" soap. Good strong soap impregnated with real pumice. By the time one gets the grease off the knuckles the hands are nice and soft. And a good stiff brush helps. If you can't find a genuine "knuckle brush" a small vegetable brush works just fine.
It's much superior to the alternative, "Comet" scouring powder, since it omits the bleach that's in most of the powders.