A Progressive use for Goose Fat.

Better to use it to make schmaltz.
Plenty of web entries on how to make it, often using chicken fat but I prefer goose.
It makes volkskorn edible, almost.
Useable as food by both sides at an eastern front game.

Is it available at Waitrose? - i'll send Raoul!

Won't animal fat go rancid after a bit? Especially if your boots are kept somewhere warm

Prior to the manufacture of petroleum based waxes & oils the popular boot waterproofers were tallows & animal oils (neatsfoot/whale oils/fish oils etc) so I'd say as long as the leatherware is looked after (cleaned & dried, not stored in plastic bags or damp places) then the boots should be OK. It may even make them edible, should push come to shove. probably slow-cooked rather than fried .

Delia Smith, Jamie Oliver and Nigella Lawson all advocate cooking your roast potatoes in goose fat which sounds a much better idea than slapping in on boots, especially since dubbin can be so easily had.

The use of animal fat on soviet footware is something that really happened, and not just some mad scheme of mine. As for going rancid, I hadn't noticed that problem with my boots myself and these where kept indoors at a cool room temperature, but as this was a winter time practise, by a field army in a very cold part of Europe, then I suspect for themselves it would be too cold for bacteria to make the fat go rancid.

I, like CW, will stick to using dubbin on my boots and keep the goose fat for the potatoes. Progressive or not I think its will be tastier that way around.

The old BW dubbin in white tubes had a very porky smell to it and if not kept freshly applied would produce mold. You can still find this in surplus stores.
Nothing wrong with animal fat on your boots but I must vote for a cooking use.

The point I was making was this would be an authentic use of left over fat, after you have stuffed yourselves silly on goose fat pototoes and schmaltz. Rather than throw it away you can apply it to a pair of clean and dry boots. (If you want to of course)