Make the very best of boot waterproofing greases yourself! Simply save all the fat off the next deer you harvest: all of the internal organ fat, brisket fat and fat trimmed from meat. Render this down by cutting it into 1"-2" pieces and placing it in a pan in a 250 degree oven for about three hours. Strain it through cheesecloth into a metal can and refrigerate until solid.
To each pound of rendered venison tallow, add a 1/8 lb. cake of beeswax and three pea sized pieces of hard pine pitch. Heat this mixture in the metal can by boiling in a pan of water. When all components become liquid stir thoroughly and you have created a boot/leather dressing which is superior to all other grease type waterproofing preparations.
To best apply, make sure your boots or holster (whatever leather item is to be treated) are slightly warm, then apply the above preparation while in a warm liquid state with an inexpensive disposable paint brush, being sure to coat the whole surface evenly, and to pay special attention to stitching and seams. When it cools there will be a film left on the surface of the leather. Take your bare hands and work the film into the leather, letting the warmth of your hands facilitate its penetration. Once properly done, your leather boots, holster, scabbard, saddle bags or whatever, will be protected for at least a full year if used daily, and perhaps several years if used seasonally.
This recipe was handed down to me by my grandfather, and to him from his father. I have used it exclusively for all of my adult life. Enjoy!