Works great to remove the dross from aluminum, or aluminum from the dross, however you want to look at it. I use a teaspoon to a tablespoon for 5 lbs of molten aluminum. But most of the time I just collect the dross that I've accumulated over time, heat it and add approx. a tablespoon into an empty soda can then smash the can. I then add this can to the molten aluminum and press it to the bottom with a steel rod. It's amazing how much aluminum you will get back, if not half of the weight of the dross perhaps more since the dross is like ash now. The dross you will skim off the top now is like ash, it will crumble into a powder oxide/ash after all of the aluminum is out of it.

In the picture below, the dross on the left is without flux added and the dross on the right is after. It's hard to see in picture but the one on the right is something like hard ash that will crumble. This same flux sells at the local hardware store for $8.00 per 1/4 lb.