Charcloth is a 100% cotton cloth that has been heated and burned without oxygen. When you go to start a fire take a small piece of the charcloth to catch your sparks and get your tinder going.
I'd never gotten pre-made charcloth that were made from cotton pads like these. They are very convenient and easy to remove one at a time, unlike with some char. They light very quickly from a spark but burn a little too quickly for my liking. I would still recommend them as there is no such thing as having too many tis of charcloth.