Filtered with dry fiber wound filters, like for water filtering. The warmer the oil, the faster it would pump. Pump was a $70 pump from Harbor Freight. Did all of this back when diesel was way over $4. As the price of diesel came back down, I lost motivation. A couple of guys I knew that were really in to it, and one guy still is I think, bought centrifuges and spun the solids and waste out of the WVO.