The $1,500 Undercoat Trap: Why Cheap Rubber Spray Rots Truck Frames from the Inside (And What Mechanics Actually Use)
Thinking about buying a can of black rubber undercoating to protect your car from winter road salt? Don't do it. Here is why hard rubber sprays trap moisture like a wet sponge—and why professional mechanics swear by simple, non-drying lanolin oil instead.