Brake fluid is a highly hygroscopic glycol-ether solvent, meaning it actively absorbs moisture and aggressively dissolves organic polymers, including automotive clear coats, single-stage paints, and powder coating. Upon contact, the fluid penetrates the paint layers, breaking the bond between the pigment and the substrate. This causes the paint to "bubble" or "wrinkle" almost instantly. Because brake fluid is water-soluble but chemically aggressive, it must be flooded and neutralized immediately with a high-surfactant degreaser to emulsify the oils and stop the chemical reaction before it reaches the bare metal.