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The purpose of this handbook is to show the construction and operation of a JRO (“Jolly Roger Oven”) char manufacture system. The JRO costs $50-90 to build, and uses the waste heat given off by a high temperature gasifier char oven (lower unit) to make a smaller batch of low temperature retort (upper unit) char. The high temperature gasifier char is ideally suited for water treatment applications and the low temperature retort char is excellent for use as cooking fuel.