I found a few tutorials on making glair for use in illumination online, and while very good they didn't answer one question. So I have to make it for myself.
For those of you that haven't looked up the other tutorials, making glair is a very simple process. First, you need to seperate egg whites from the yolks, being very careful not to allow any yolk fat into the white. Then you beat the egg whites until they're stiff, the same process as making meringues. Or if you don't know how to make meringues, whip the egg whites until they've changed from a liquid to a white froth. When you think it's stiff enough, tilt the bowl gently; if the froth starts to slide, then you need to whip a little bit more.
When my egg whites were whipped, I covered the bowl with a tissue and left it overnight, on the counter out of the fridge. The next day, the glair liquid can be gently poured out of the bowl and into a jar for keeping. I opted to throw a clove into the jar too, to keep the smell at bay as the glair ages.
And the question that I wanted answered? What happens to the fluff after the glair is poured off? I thought it might still have been similar to whipped egg whites, but it turns out it's more like medieval styrofoam. Good to know.