So, if I buy 1 CL at $20.00 and the price goes to zero then I will lose $20,000? But if the price goes back to $60, then I'll have $40k profit?
No, if you buy 1 CL at 20 and the price goes to zero, you will be at 20K unrealized loss. You only lose when you close your position. If price goes back to 60 bux, and you close at that price, you will make 40K.
The real trick is timing the expiration of your futures contract positions.