Most any cotton or linen clothe will work. Just make sure that it does not have any synthetic/nylon in it. Those modern manufactured materials melt. And the more used or washed your clothe is, the better it seems to work when charred.
Most people over on this side of the pond tend to use a small candy/losseng tin to make small batches of charclothe - like Suckrets or Altoids. The Altoids tins tend to be more available - at least over here. You might also look to see if you have a tin bandaid container. They also work well and aren't too big. And I've used a small 1/2 pint paint/varnish can before. I just burned any residue out of it first, and then punched a nail hole into the lid.
A friend came up with a method of making charclothe without a "tin" a few years ago for his historical demonstrations. He couldn't find any documentation for those "tins" before the mid to late 1800's. So he came up with another method.
What he does is cut/tear his cotton or linen clothe into long strips about 2 inches wide. He then wraps that clothe around a small stick/twig (as big as a pencil or so). When he has wrapped it up until that "bundle" is around 2 inches thick, he then tosses it onto his campfire. That starts the whole OUTSIDE of the clothe on fire. When it has burned a bit, and the flames are dying down and the bundle is now "glowing" red on the outside, he then buries it in the dirt. This smothers the burning bundle.
When it has completely cooled, he digs it out. He now has "charred clothe" all around the outside of the bundle, with it getting progressively less charred as you unroll it. To use, he just rolls off a few inches and tears it off. He then stores the rest in a leather pouch. That stick in the center helps protect the charclothe, and the pouch helps keep it from getting all busted up - and getting black gunk over everything else in your pack.
As he unrolls and uses his charclothe, it starts to get more brownish - less charred. That's the center parts that the fire never got to. When it won't catch a spark easily anymore, he tosses the bundle back into the fire to "char" some more - and then buries it in the dirt to put it back out.
This method does work fairly well. The only real drawback is that you end up waisting some clothe. Some gets burned/charred too much, and some gets under "cooked". But it is just a continuing "work in progress".
So you don't need a "tin" to make charclothe. There are other ways. I even know one guy that took a bean can, stuffed some cotton shop rags in it, smooshed the open end together fairly tight, and tossed it in the fire to "char". It's a one-time use method, but it worked! And he had the charclothe he needed for the Flint-n-Steel Fire Starting competition an hour later.
Just some humble thoughts to share. Take them as such.
Mikey - yee ol' grumpy blacksmith out in the Hinterlands
p.s. Yeah, me and some friends of mine are kind of hard on shop-rags. We use them for more things than just wiping oil/grease/paint. Our biggest problem is not being able to find one when we really need one. But that's also what jeans and shirt sleeves are for! (and I do my own laundry, so I also know the consequences of such actions!)
Someone else will probably answer that question for you.
