Waterproof, soften and add life to your boots, saddle, or other leather products by using neatsfoot oil. Neatsfoot oil is an oil taken from the bones of cattle and is an excellent conditioner and weatherproofing agent for leather.
CLEAN YOUR BOOTS FIRST! Skip this step if your boots are new, of course, which is an excellent time to waterproof! You may want to remove the laces if you have lace-up boots and just get them out of your way. Wipe or even wash off the excess dirt, oil and grime with rags and/or a soft brush. Then use saddle soap (recommended) or another leather cleaner. Using one rag, scrub the leather down until you work up a lather. (Doing this works additional dirt and impurities out of the leather itself.) Then with a second, clean rag, wipe the saddle soap from the boots. It's best to leave the leather overnight or at least a few hours before moving on to Step 2.
Using a fresh rag, apply neatsfoot oil to boots. It is not necessary to try to work the oil into a lather as you did the soap. Just apply generously, taking care to work the oil into every nook and cranny, before gently dabbing excess from the leather. Don't wipe off the neatsfoot oil!
Let boots stand overnight before wearing. You've just extended the life of your boots by cleaning, conditioning, waterproofing and preserving the leather.