Char cloth (or charred cloth) is a swatch of fabric made from vegetable linen, such as cotton, that has been converted (i.e. decomposed using a process call pyrolysis) into a slow-burning fuel of very low ignition temperature. A single, small spark placed on char cloth will ignite the cloth which will begin to glow red. The slow-burning char cloth can then be used to ignite a tinder bundle to start a fire. Char cloth has been used by primitive men for ages. The. great thing about char cloth is that once ignited, it will continue to produce smoldering embers for a minute or two giving you plenty of time to place the cloth into a tinder bundle and blow on it until the bundle ignites and begins burning. It is much easier than trying to light the bundle using a quick burning spark.
The easiest way to make char cloth is in a tin, such as an Altoids tin. A tin can with aluminum foil pressed over the top can also be used (poke a small hole in the aluminum foil). Begin by punching a small, nail-sized hole in the lid that will allow gases to escape while the cloth is heated inside the can.
Next, cut 100% cotton cloth (T-shirts or old cotton terry-cloth towels that are loosely weaved are the best) into small squares about 2 inches square and place the squares inside the can. Do not pack the cloth squares into the tin – simply lay them in gently. Then put the cover back on the tin.
Set the tin on a small, calm fire or a fire that has burnt down to coals. Soon you will see a stream of smoke coming from the hole you poked in the can. Leave the tin in the fire until the smoke stops (around 15 minutes). Do not remove the lid from the tin until the smoke has stopped coming out of the can.
Remove the can from the fire and after allowing it to cool, carefully examine the char cloth. It may take a few tries to get the char cloth just right. If it is merely browned then it has not been “cooked” long enough. Put the lid back on the tin and place it back in the fire. If it is black and crumbles easily when touched then you cooked it too long. Start another batch but remove it a bit sooner. If it is black, but not too fragile, then it is perfect char cloth. Carefully separate the cloth pieces.
Char cloth is best stored in an airtight container such as a sealed, plastic bag.