I've found that "Worx" powdered hand cleaner works very well. No petroleum products at all, and is very effective. Does not dry your skin, and you don't need too much to do a good job.
Snap On sells it, but it is MUCH cheaper to buy it yourself. With 3 guys using it multiple times per day, a 4.5 lb container lasted 2 1/2 - 3 months.