So, does anyone have any clever, easy, simple, non-messy (mostly) ideas on how to grind up about a cup of charcoal at a time? I have a mortar but no pestle, and haven't been able to find a suitable rock.
Got a dowel? A pestle need not be made of stone, a dowel will work (spare handle)
Or you could imitate fowl and make a gastric mill
swallow some gastroliths and shake shake shake shake (charcoal + marbles/gravel + drum = ball mill