"But no cleaner ever gets the black out of the deep cracks in my hands from 50 years of over use, scares and wear and tear!!! "
Red Scotch Brite and Ivory bar soap, the heavy duty pads NOT the painter scuff pads.
It will take off almost anything (paint, primer, glaze, bondo, grease, chassis black, tar, ect.), does clean out the cracks and does not dry out your skin. I would suggest using a hand lotion after you dry off.
It does not remove scars and it doesn't like windshield urethane (use solvent first) but everything else comes right off.