Dry-wiping is the act of using a microfiber towel or duster on a dry, contaminated surface without a dedicated lubricant. On a microscopic level, even a "clean-looking" car is covered in sharp-edged silica (dust) and airborne fallout. Without a surfactant-based lubricant to encapsulate these particles and provide a "hydro-wedge" between the towel and the paint, the grit is pressed into the clear coat and dragged across it. This creates linear abrasive shear, resulting in deep, straight-line scratches that are significantly more difficult to polish out than standard circular swirls.