The size of the granules of carbon indicate the state of seasoning of the wood or the temperature at which the ash falls out of suspension. In this case it looks like its the temperature, as the wood appears to be ok., (from here) so split that wood into at least three pieces for when you start the fire. (still use the kindling obviously) Once it settles down then use the bigger size. You shouldn't need to clean that ash out for weeks and weeks at the very earliest. To clean the flue set a fire with the smaller sized wood described and run it wide open for 5-10 minutes once the heater is hot. You don't need and flue cleaners if the fire is operated correctly. That fire is in an old fireplace isn't it?
