* Dead skin cells: Our skin constantly sheds dead cells, and soaking in water loosens them, making them easier to wash away.
* Body oils (sebum): Our skin naturally produces oils to keep it moisturized. Some of this washes off in the bath.
* Dirt and debris: Environmental dirt, dust, and pollutants accumulate on the skin throughout the day and get loosened by the water.
* Products: Residue from soaps, lotions, deodorants, and other skincare products can also contribute to the gunk you see in the bathwater.