Burning Wool

I have just taken my latest length of felt out of the oven, it is coloured bright pillarbox red and I want it to have a dark edge the grey dye didn't take I think maybe fabric gets tired of being dyed after a while and it refused to take the dark grey and just looked dirty so I coiled it up and put it in the oven and burnt a black edge on it - when you really burn wool it crumbles like toast - who knew?