Fat liquor is used to oil, soften and preserve furs and hides. The oil treatment can be purchased pre-made at most hunting and outdoor stores, or you can create your own from sulfated neatsfoot oil. After the hide or fur is removed from the animal, cleaned and then salted, fat liquor can be added to the fur. Once fat liquor is added, the fur or hide should be dried out and cleaned. Improperly drying out the fur after fat liquor is applied can damage or destroy it.
Combine 3 1/2 ounces of sulfated neatsfoot oil, 3 1/2 ounces of warm water and 1 ounce of household ammonia in a bucket. This is enough mixture for a 10-pound hide. Adjust as needed for larger or smaller hides.
Lay the hide, hair side down, on a flat surface.
Dip a clean, soft-bristled paintbrush into the oil mixture. Spread half of the mixture evenly over the hide.
Allow the mixture to dry on the hide for 30 minutes.
Spread the second half of the mixture evenly over the hide.
Cover the hide with a sheet of plastic to prevent the moisture from evaporating. Allow the mixture to work into the hide overnight.
Remove the plastic from the hide. Drape the hide, hair side out, over a pole, sawhorse or something else thick enough to hold the hide. Allow the hide to air dry until the flesh side is only slightly moist.
Position the hide, fur side down, over a sheet of plywood. Gently stretch the corners and hammer them into the plywood. This helps stretch the fur. Once the flesh side is nearly dry, remove the hide from the plywood.
Pull the hide in various directions to stretch and soften the hide. If needed, run the flesh side of the hide over a wooden edge to soften the hide further. Repeatedly do this until the flesh is completely dry.
Fill a sawdust tumbler to the fill line with clean sawdust. Place the hide in the sawdust. Tumble the hide in the sawdust tumbler to clean and brighten the fur. Remove the fur once the tumbler cycle is complete.
Brush off excess sawdust.
Fat liquor should be applied to fresh furs and hides. It should not be used on furs that have already been dried, tanned or treated.