Well, if I ran lamb in this pot, that might come in handy; lamb fat congeals at a different temp than other common meat fats and is harder to eradicate. The method I used worked quite well for the chickenfat (maybe because I never let it cool).
Now that I know how well this worked, I am lusting after the much bigger unused urn at the parish kitchen. This one I have now will make about a gallon of stock, assuming I fill it halfway with meat and veg and top off the water. The one at the church is about twice that size. It would hold an entire chicken for instance, easily, without having to cut it up.