Nick,I'm interested in seeing how you'd collect it and the process for cooking the fries this way.
Nick,
I've saved and frozen the fat trimmings from briskets, then chopped it up, and heated it in a pan over medium heat.
A crockpot would probably work well too.
Didn't McDonald's cook their fries in beef tallow up until the 80's or sometime around them? Isn't that why they were so much better back then?