A process for heating used lubricating oil (ULO) to dehydrate and/or recover distillable components therefrom, is disclosed. The ULO feed is heated by direct contact heat exchange with a non-pyrolyzing molten fluid, molten metal, or molten salt, preferably maintained as a continuous phase bath, operating at a temperature above the boiling point of water and below 600 DEG C. The ULO feed is heated and at least partially vaporized in, or above, or by contact with the molten fluid. Lubricant boiling range hydrocarbons are recovered as a vapor product. The additive package in the ULO, or decomposition products thereof, are recovered as a liquid phase.