At one of my jobs, we built one out of a 55gal. drum cut in half vertically. Made sure to center the large bung on the bottom to be the drain. Small angle iron welded around the cut edge and angles down the corners for casters. Then made a hinged lid of angle frame and expanded metal to catch drain plug and set filters on to drain. An old electric motor and a used hydraulic pump mounted on the wall of the shop with a hose running outside to the waist oil tank. Worked great, just had to set the end away from the bung, up on a block to empty the barrel.