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
