G'day, Next time use two drums, a 55 gal drum, remove both ends cut 4, 2 x 2 inch air inlets to light fire later, the top needs a cover and a chimney (I cut up a second 55 made a fitted top with 2 inch lip and chimney, cut remainder lengthwise roll compressed and tied and inserted now having a lined fire box) and inside a inverted smaller dimention container/bucket about 2 inches shorter than the 55 (robust construction)(I use a discarded electric hot water cylinder one end removed) tightly packed with material to charcoal stand inverted on the disgarded bottom of the first 55 no airspace required. This internal container/s should take up 1/2 to 2/3 of the 55 gal drum, now place 55 cylinder over the inverted container after putting some paper and deal on the bottom fully pack the drum with good hot burning wood, NOW place a crushed alluminum drink on top of the container, put on top with chimney (for safety you can place a disgarded paint tin over chimney as a spark arrester) and light the fire. I light mine at 7 am, the NEXT day 6 am dismantle, remove top check for aluminum can if melted temp was greater than 660 oC and the charcoal will have a high surface area, remove 55, clean away ash now harvest clean charcoal. I make one a day (slow) but over a year I have sufficient to put below the soil surface as I consider this charcoal as ONLY microbial accomidation. I demonstrate this to farmers, gardeners, landcare groups anybody interested, I call it "The Sunday Roast" system. Trust it may be of interest, Regards, Douglas.