Here's a couple shots of my gasification chamber (porno for pyros) going pretty well. It's hard to get a good pic, but one is with flash and the other without. The point of gasification is that the smoke all gets burned up, so that none goes up the stack. If you don't see any smoke in the gasification chamber, you're getting a clean burn. There's no smoke visible in the flash shot, even though the flames are much bigger in person. The firebrick isn't glowing orange yet because I just fired it up.