I get very good char cloth from an old 16oz. beer can. Cut the can in half so you have the bottom and top of the can as separate pieces. Cut a few vertical slits in one piece so you can fit it into the other. That tab that was originally in the drinking hole, push that back into the hole to mostly seal off the oxygen. Then just add some material to char. I like old socks, towels, sweatshirts, punkwood, grasses and bits of softwood. Put the can back together and cook until their is little smoke still coming out. Let cool and pull the can apart to get your char. One thing nobody seems to mention is that anything charred will absorb moisture from the air. Your char will go "stale" if exposed to humidity. Keep it sealed and fresh.
I took some cotton rope and put it in a small Altoids tin and cooked it watching the flame start and stop out of edges of the box and it was done. When doing the bow drill, the char cloth lights easily, once a coal is made . However it is also jet a easy to use cotton and Petroleum jelly , but you can't make it in the woods.
Nope. More than two dozen natural materials that will catch the sparks from Flint the rock and Steel. Believe I covered that in previous posts in this thread. (aka Post #28) Also, Paul from Malaysia does an excellent job of covering this in the Advanced Flint & Steel article I provided a link to previously. Do try to keep up. ;-) hee hee hee :-D