Thats hilarious! Someone gave you a pair of antediluvian boots, and youd like to salvage them. Im trying to remember when I last saw a pair of the Trappeur boots; it was a long, long time ago. Theyre probably closer to 30 years old than 20.
Personally, Id nail em to a plank and hang them on the wall in my drawing room. Theyre antiques and should be treated as such. Whether theyre even still wearable is hard to say. Leather shrinks a bit over time, and the toes curl. So that might be an issue. And I really doubt the stitching has all that much life left in it.
But you can try to breathe some life back into them. Id start with just a very small amount of mink oil or something else thats a little bit greasy. Work that in thoroughly and then just massage the daylights out of the leather. Over that, add a layer of Sno-Seal ($5 a can; atsko.com) and repeat the massaging process. I imagine the leather will drink all this right up. Then lace them on and dont do much but sit aroundwear them while reading or watching TV. Let the heat from your feet help shape the leather. Then try some hiking.
After that, Im sure youll feel motivated to run out and buy a pair of Asolo Fugitive GTX boots ($170; asolo.com), with modern construction, excellent leather, and a Gore-Tex liner.