Durty Cloth Tool Crack |verified|ed Best -

When you drag this over a surface (old leather, failing clear coat, crazed acrylic, or weathered wood), the cracks act like saw teeth. The dirty cloth deposits grime deep into the fissures. Standard cleaning fails because you are wiping more contamination into the gaps.

You see a dirty crack, so you rub faster. Friction heat from a dirty cloth melts soft plastics and rubber. The dirt then thermally bonds to the crack edges. Permanent black burnishing. durty cloth tool cracked best