Mink oil, obtained from the fatty hide of a mink. protects leather from moisture, salt, and other damage from dirt and the environment. It also softens the leather, making stiff work boots and hiking boots more comfortable to wear. The mink oil that's sold to condition leather boots is mixed with beeswax, which maximizes the conditioning benefits. Tubs of mink oil paste are available at most shoe stores, sold alongside other waterproofing materials.
Warm the boots with a hair dryer, or set them over a heat vent for a few minutes. Heating the leather helps it absorb the oil.
Spread the cloth over your fingers, and scoop out enough of the mink oil paste to cover your fingers from the first knuckle to the tips. Rub the mink oil into the boots until it turns clear and begins to melt into the leather.
Repeat Step 2, conditioning your boots one section at a time, until both boots have been covered with the oil.
Wipe off any oil that got on the laces or soles of the boots.
Allow the boots to dry overnight, and apply a second coat of mink oil in the same way.
Mink oil may cause some leather to become slightly darker. Test it first on an inconspicuous section of one boot.
To apply the mink oil, a chamois cloth works well, or simply use a scrap of flannel from an old shirt. Paper towels will work if that's all you have.
Mink oil will not damage non-leather parts of your boots, so there's no need to be too careful about the application.
Reapply the mink oil every few months to keep your boots protected.
Mink oil can also be used to condition other leather products such as baseball gloves and leather clothing.