I converted my 40 year old oil stove to wood, by putting a pan over the air entrance/oil burning puddle to distribute the air through the 20 or so half inch holes i drilled into it. IT works great for me, its not as dangerous as a waste oil heater (old oil has clods which will make you open the ball valve a bit more to keep it burning, untill the clod is through and the oil is heated so it runs down like gasoline, drowning the fire and overflowing into the shop)
I could only burn an entire year of oil changes in just 3 winter days. Nowadays i just throw a pint of oil over the wood everytime i light it. (with the propane torch) That will help me get rid of my old engine oil, but its safe to stack a wheelbarrow full of wood in it and let it burn. With engine oil i had to adjust the flow every 15 minutes, and my workshop was full of thick oil smell...