Track marbles are "slugs" of hot, molten rubber shed from racing slicks during high-performance driving. When these "marbles" impact your vehicle's bodywork at velocity, they undergo thermoplastic bonding, essentially melting into the pores of your paint, vinyl wrap, or PPF. Because racing rubber is designed for maximum adhesion, it cannot be removed with standard car soap. Attempting to scrub them off dry will lead to heavy marring and scratches. Safe removal requires a chemical solvent that can penetrate the rubber's polymer chain and release the bond from the substrate without damaging the clear coat.