Dye transfer is a form of molecular migration where unstable pigments (typically from indigo denim, leather belts, or low-quality apparel) bleed into the top-coat of automotive leather or vinyl. Because most modern car seats are "coated" with a protective polyurethane layer, the dye doesn't just sit on top, it leaches into the microscopic pores of the coating.

If left untreated, the dye can become a permanent part of the finish. Successful removal requires a high-surfactant emulsifier that can "lift" the pigment from the pores without dehydrating the leather or stripping the factory-applied clear coat.