Possible Clues:

• Kind of fuel made by burning wood
• Burn one fuel to get another
• Black fuel made from wood, good for barbecues (8)
• Grey or black drawing medium
• Artist, initially in depression, keeping up daily drawing
• Black stuff for burning or drawing
• Result of burning wood in the absence of air
• Form of carbon for drawing
• Drawing fish caught initially on a line
• Cleaner fuel creates carbonaceous residue