Plenty of homemade creasote formulas online. We used to just soak the bottom few feet of posts in a barrel of used motor oil cut with diesel.
googled this-
5 gallons of coal tar roofing or driveway sealer, 5 gallons of Diesel Fuel, 5 gallons of used Diesel oil, 2 lbs of feed salt Stir well with an old shovel.
Might work best to dissolve the salt in the diesel fuel before mixing in other ingredients.
