I had a wiring harness in my back seat for about a month. I have tan interior. THe black tape from the harness left black marks everywhere. I tried some leather cleaner and "tuff stuff" but no luck. any suggestions

 

Try to scrub it off with the soft nylon brush (or old toothbrush) with some mild soap, don't try too hard and keep a dry cloth and remove any water and soap the moment the stains come off. After that, any leather polish, or leather moisturizing wipes should be applied. I had a similar problem with the dark brown stain on my platinum leather...i guess it was a varnish that leaked from a can, which my stupid girlfriend happened to place it on the seats.

 

Alternative cleaning solution - use a formula that is used by one of the major tanneries to clean their leather - 3% Woolite® or Dreft®, 10% Isopropyl alcohol and the balance distilled water. It may be necessary to repeat the cleaning process to get it back to a matte finish.

 

Seems like it will work. Thanks.