Cheesecloth? Vintage ad promotes milk-fiber shirts
Casein isn't cheese, as J. Brad Hicks described it. Instead, it's the stuff that makes cheese happen. If milk is the liquid and cheese the solid, casein is the stuff that facilitates the transition — the casein in milk clumps together and solidifies into cheese.
So, in a way, Aralac really was cloth made from cheese. During World War II, when wool was scarce, it made a lot of sense to buy Aralac — which was significantly cheaper and easier to get a hold of.
Which is all well and good, but really, the best part of the article is the charming old magazine illustration that sparked the whole thing: