Thanks,
I will experiment with charred cloth. I guess I will go for hiking soon anyway and collect some grass around to check as well. Pity I cannot find my reserves of Cramp Balls, they are such a good tinder...
I have Swedish firesteel and get fire quite easily with it with many natural tinder I can find aaround, but I want to learn to make fire without relying on anything not natural, i.e. no high carbon steel or Swedish firesteel, just rock flint and a stone. However, I can start practicing with not natural tinders in order to increase confidence.
By the way, I tried to make fire using Swedish firesteel and my rock flint - it worked very well!