Loyd said:
If the spot that lights runs up a single strand of fabric or in one direction only, the char cloth was probably over cooked. I put my 100 per cent cotton cloth into a tin and throw it into the fire. Before the smoke stops I pull it out with tongs and plug the hole with a stick sharpened on one end. When the tin cools down I open the lid and test the char. If I see brown, I throw it back in and re-cook for a while.
In my experience, making char is a pretty forgiving process. All I do is loosely roll a coupla feet of 100% cotton or linnen canvas, or much less expensive 100% cotton denim from old jeans and place it in an old tin film canister.
A small hole is drilled through the side of the lid and the side of the can, with the lid in place.
Rotating the lid to align the holes when making char, and rotating the lid so the holes do NOT align protects excess char in storage.
The tin is placed in coals and turned over a coupla times to insure an even char until smoke stops issuing from the hole. The tin is then raked away from the coals and allowed to cool.
In my experience, there is no need to pack in mud, plug any holes, or do anything other than let the tin cool.
I have never had any char turn to ash by allowing the escaping gasses ignite. Igniting the escaping gasses MAY have some effect on the quality of the char, but I don't know what it would be.
Opening the can before it cools completely WILL turn your char to ash.
Like Loyd, if there is any brown, I just throw it back into the fire for a while.
I very much prefer heavy fabric for char. I seldom attend rendezvous these days, but I do a fair bit of trekking in all sorts of weather and I want char that will hold a spark long enough to generate sufficient heat to dry slightly damp birdsnest material.
J.D.