Why is it hard to open a tight container, like a jar lid or bottle cap, with just your bare hands, but when you grip with your shirt or a piece of cloth, it becomes no effort?

Question

Why is it hard to open a tight container, like a jar lid or bottle cap, with just your bare hands, but when you grip with your shirt or a piece of cloth, it becomes no effort?

In: Physics

Answer 1

Friction

Your hands are full of oils and moisture that act as a lubricant on smooth surfaces like a metal lid. Your shirt removes this factor which results in more friction.