This is actually whole milk on a white pot. First fired at cone 04 in an electric kiln. I brushed the milk on and refired in the BBQ for about an hour at 600 degrees or so. It's now waterproof. Why you wonder? Prehistoric pots in England show resides of milk, I think a kind of glaze. Waterproof too. It works much better than fat. I also tested pork, butter, goose, and wax. Milk was best. So did a whole pot and cooked some broth with bones and onions. Works like a charm. But I need to get it onto a wood fire.