A process to oxidize an olefin wax, comprising: contacting a feedstock olefin wax composition with an oxygen-containing gas at a temperature greater than a melting point of the feedstock olefin wax composition melting point, to prepare an oxidized olefin wax composition wherein the oxidized olefin wax composition has an acid number greater than 1 mg KOH/g oxidized olefin wax composition and a kinematic viscosity at 100.degree. C. less than 70 cSt.