Custom refining is a slow, thorough and mild method of removing impurities. The oil is not damaged and it retains all its desirable lubricating qualities.

No residiums are used in the maufacture of quality custom-built lubricants. Oils used in the manufacture of custom-built lubricants are not subjected to harmful "catalytic cracking" for gasoline. All the natural strength of the oils is thus retained for lubricating purposes.

Commercial refining techniques are faster and cheaper but are drastic processes. They remove many of the desirable elements as well as the undesirable.

Many commercial grade lubricants are made from a "residium". Residium is what is left after the gasoline and other light ends have been removed. The residium is so weakened by the drastic methods (catalytic cracking) used to extract gasoline that its lubricating qualities are seriously damaged.