Take a pound or so of parafin wax and grind it up with a cheese grater. Soak it in a half gallon of mineral spirits until all of the wax is dissolved. This might require allowing it to sit in a closed container for a couple of weeks. Stirring will cause most of the wax to dissolve, but soaking should take care of the rest. Generally try to dissolve as much wax as the mineral spirits will hold.

After that, dump in a couple of pints of mineral oil (less of a smell) or non-detergent motor oil. If the mixture is thick, thin it further with more mineral spirits until it is of a sprayable consistency.