For those asking.. the white powder is borax. a cleaning agent used to remove impurities from the fire and prevents oxidation.Great skill. And at least he’s not risking damage to his safety glasses. Keep them in their case and on the shelf, out of harm’s way.Really mind blowing to me that someone of the skill set and experience is doing all this without ever wearing safety glasses and protecting his eyes - without them he would no longer be able to do this trade.