ELI5: Why does wrapping a bottle cap in a towel or rubber band make it easier to open?

Wrapping a towel or a rubber band around a bottle cap makes it easier to open because it gives your hand more friction, stopping your fingers from slipping.

Imagine running on a smooth, wet floor while wearing slippery socks; your feet slide everywhere, and you cannot push forward. But if you wear sneakers with rubber soles, your shoes grip the floor, and you can push off easily.

Opening a tight bottle works the same way:

• Stopping the slip: Your hands have natural oils that make your skin slide right over smooth plastic or metal. A rubber band or a rough towel creates strong grip, which prevents that sliding so all your strength goes directly into twisting the cap.
• Protecting your skin: Squeezing a tiny, hard cap tightly can hurt your fingers, which makes you pull your hand away. A soft towel cushions your skin, allowing you to squeeze much harder without feeling pain.
• Making the cap bigger: Adding a thick layer makes the cap slightly wider. A wider cap acts like a tiny lever, meaning your hand needs less effort to turn it than it would on a very small lid.