This song reminds me of my dad. He's worked on cars most his life. His hands are often black with the chemicals he uses and I wonder if he just dont wash his hands good or if his fingertips are just permanently stained black as I've never seen them not black and dirty looking even if he just washed his hands. He breathes exhaust fumes all the time, and metal shavings. It's not the same but it's what I'm reminded of.