Katsuki pulled into the long dirt driveway after a few hours of working down at Kirishimas mechanic shop. As he stepped out of his slightly beat up, muddy Chevy Silverado it became clear he didn't go there just for fun. His hands and forearms were almost completely black with oil and grease, as was his white tee stained with soot and oil. You can visibly see the hand marks where he wiped off his hands on the shirt, actually.