What are you doing with the ingots?
I simply melted down random scrap into ingots that are sized to go back into the cuppola. The point being that every time you melt/pour metal, it tends to become a little bit purer. (If you do it right) Also, it makes it easier to store.
So in future, I know that when I add an ingot to the foundry, every ingot of Aliminium I add will be about 1lb. Plus a small pile of ingots look more impressive sitting on a shelf than a barrel in the side yard full of scrap
Today, I modified the burner to hopefully be more efficient! Don't know if I'll get around to testing that this weekend or not though.