BECAUSE YOUR FOOT IS A DIRT-LOVING SPONGE
You can’t always see it, but the microgrooves in the bottom of your feet as well as the squeezed spaces between your toes are constantly collecting millions of microscopic bits of dirt, bacteria, fungus, oil and viruses that build up quietly throughout the day. No matter where you’ve been, your feet are probably a lot dirtier than you think. And your very clean sheets don’t appreciate you bringing your day home with you into bed.