Before I go to the shop wash sink to clean up, if I'm especially greasy, even with undercoat smears, I pour some fresh motor oil or atf in my hand, rub it all in and wipe off with a cloth. Works great and skin doens't feel like it going to peel off. Black greasy dirt from an older vehicle, black gunk from the bottom of an oil pan, all loosens up with some fresh clean oil. We have been advised at shop meetings, to get used motor oil, and gas and diesel off the skin immediately. There are a whole bunch of acids in used oil, and a whole world of additives in fuel that weren't there the first 50 years. Before tying into something really dirt, like Papaw said, rub in some hand lotion, it makes a barrier on the skin to keep out the dirty stuff, unless you really think those black creases on the fingers and the palms of the hands is a sign of your occupation. Another thing, 3-M yellow adhesive, that wonderful sticky stuff that stays on the finger tips for days? Before it gets dry, it will rub off with some ATF. Gasoline voltatility, yeah, in the army I was taught that a gallon of gasoline, properly vaporized has the same energy as two one pound sticks of TNT.