There are a few ways of making tinder,
I use this one because it uses waste materials that were available to most peoples from the Iron Age onwards. Firstly we need scraps of pure linen cloth, I use linen for most of my under tunics so there are often trimmings to be found. I presume the same would also be true for our ancestors so it seems a good starting point. The authentic way to do this next part would need a clay pot with a well fitted lid, I have tried this so I know it will work, but for ease of production I would
recommend an empty shoe polish tin to start with. Pierce the lid of your tin with a small hole and then put it into a good fire to burn off any residue of the polish. Remove the tin and let it cool. Now pack the tin with as much of your scrap linen as you can fit in without it hanging out of the edges when the lid is replaced. Return the tin to the fire in a spot where you can observe what happens.
Our tinder is going to be a form of charcoal so the object
is to part burn the linen in the tin with a minimum of oxygen. We can watch the tin to see when it is ready. The first signal is a plume of smoke issuing from the hole in the tin lid, this is often, but not always, followed by a jet of flame. The heat of the fire and the amount of linen will dictate how long you will have to wait until all the smoke and flame have ceased. Now remove the tin carefully with some tongs and let it cool.
When the tin is opened
you should see a blackened wad of cloth-like material somewhat smaller than you put in. This is your tinder and if you break a sheet off, you should be able to light it with the sparks from your flint and steel to create a glowing red ember. This ember should smoulder for some time and if you blow on it it will spread faster.
The final ingredient needed is something to turn our ember into a flame. For this we can use waste linen again.
When flax or linen is combed before spinning, the coarse and broken fibres are often discarded. This scrap is called "tow" in Old English and almost the only thing you can make of it is a poor cloth called "tow rag". However if it is very dry it is quite inflammable due to a high content of linseed oil. If we take a small amount and wrap it around our glowing tinder, we can now blow upon the ember and as the ember increases the temperature of the tow it should burst into
flame quite spectacularly. Mind your fingers, beards or long hair by the way.