I had my white signature leather done a year ago when the car was new. Drivers seat has dye transfer at the belt line on the backrest. I have tried a number of leather cleaning products to get it off but no dice. So far, contrary to the paint treatment which i think is great, i am unimpressed with the leather treatment. My car goes in next 16th December for its annual Opticoat maintenance treatment to maintain the warranty, and i will let the pro have a go at it. if he can't clean it, then i will officially report it as a waste of money and time. The Opticoat glass treatment is also a waste of time.