Black scuff marks from shoes can be easily removed with a safe cleaner and a magic eraser. In my detail business I use simple green fresh scent cleaner for wheels,interiors,carpet,wheel wells,tires and engines. Its not caustic and works very well. I buy it by the gal at home depot, its blue in color. Twenty years or so ago, I would buy from  my detail supplier, carpet  shampoo, vinyl cleaner, leather cleaner,engine degreaser. All of these products cost alot of money ,so through the years experimenting to cut costs but not sacrifice quality, i found fresh scent by simple green to work  great.I Always water it down. I will pour about a cup of cleaner in a quart pump sprayer and fill with water. Thats a good dilution ratio. Now back to scuff marks,take a magic eraser fully wet it and wring it out. Spray cleaner on eraser and scrub mark away, follow wiping area with a terry cloth towel. This method also works well on arm rests,door panels, and leather or vinyl seats. To get more Auto Detailing tips go to my Detailing Blog at Nu-Sheen- Also check out Meltdown Bug Remover