I'm not much of a believer in magic. It has to be getting out of the system some way. I would start it up on dry pavement and let it idle until the thermostat has been open enough time for any escaping liquid to make it to the ground possibly 10-15 minutes after it opens. Watch the exhaust for steam. Then shut it down and go over the radiator, cap, hoses, reservoir, and the water pump. Don't forget the heater inside and it's hoses. If that produces nothing, look at the oil and the air filter for any signs of liquid.
If, after all that, there's no sign of coolant escaping anywhere, I may change my belief about magic. :-)