You probably just mopped the floor. Somehow, there is already a black streak by the fridge. You scrub hard, but it barely comes out. Sounds familiar? Turns out, that streak may not even be dirt. According to the study, ‘Analysis of factors influencing the friction coefficients of shoe sole materials,’ published in the journal Safety Science, which reviewed shoe-floor friction research, repeated contact between shoe soles and flooring wears down surfaces over time and can transfer rubber material from the sole onto the floor. That is basically what a scuff mark is, and the fix might already be in your garage: a plain old tennis ball.
Why does that black streak keep showing up
A scuff is not a stain sitting on top of your floor. It is a thin layer of rubber that has stuck to it. Sneakers, chair legs, and rubber-soled sandals all leave little bits of material as they slide across a hard surface. According to the study published in the International Journal of Industrial Ergonomics, floor surfaces show measurable topography changes even in the early stages of repeated rubbing from shoe contact, which lines up with why the same doorway or kitchen corner in your home tends to collect marks over and over.
The real reason a tennis ball works
A tennis ball isn’t just a rubber core. According to the International Tennis Federation, every official tennis ball is made by gluing two rubber hemispheres together and covering them with felt. That felt layer is the right coarseness to get the rubber smear off your floor without being abrasive enough to scratch most sealed surfaces. By rubbing the ball back and forth over the mark, the felt creates gentle friction that lifts the stuck rubber instead of smearing it around like a regular cloth.
