"A drum of crude shale oil was secured from the Bureau of Mines Shale Oil Development Plant at Rifle, Colorado for experimental filtration work. This oil is the product from their N-T-U retorting plant. The oil as received contains small percentages of emulsified water and rock dust. Preliminary studies to remove these contaminants by filtration were made. Effect on rate of flow of temperature and percentage of filter aid was investigated using H7flo Super-Cel and Celite 503. Increased rates of flow were obtained at the higher filtration temperature. Rates of 7.9 gals/sq ft/hr with 0.4 per cent Hyflo and 9.0 gals/sq ft/hr with 0.4 per cent Celite 503 were obtained at 900C. In both cases, rock dust and water content were substantially decreased."