Thanks for the ideas, I will have another go at some dusters, see if I can find a brand without contaminants in. I spent a lot of time testing different materials a few years back; ended up writing an article in Bushcraft and Survival skills magazine on it. No material I tried came close to 'good' dusters. I could get a spark to catch on most of the materials mentioned but not every time. If you are trying to teach a child and they are struggling to get a spark it is really important that when they get one, that very one will take on the charcloth. Again this relates to traditional flint and steel firelighting, not ferro'.