Cotton Wool is good in fairly calm conditions as it gives a big flame quickly, to make it last longer apply a bit of vaseline (petroleum jelly) as this gives a considerably longer burn time. For charcloth I use old gash canvas (retired 1950's army tents who have finally died...) which I have access to a near endless supply. This I prepare in an upturned A10 size tin with a marlin spike hole punched in the base, an a saturday nights camping I put it upside down next to the growing fire and build up around it. This I leave overnight- in the morning it's cooled down an is great stuff- as its so thich and tough to start with it is still stong enough to fold and carry in a plastic bag for weeks at a time.
If you allow any oxygen (air) into the can before it is fully cooled the charcloth will instantly burn (as some of you found out!). With lighter cloths you will probably need to remove the can sooner(make sure no air gets in though!) and always pack the cloth tightly (again to minimize air available for combustion). Charcoal can also be made in the same manner, but the bigger tins are better as you will of course need larger quantities.
Hope this helps, Blue Sky!
Jim. :bu: