Abstract: A substantially liquid, aqueous, rare earth oxide based composition for preserving the luster of the smooth surfaces of objects needing to have such an appearance. The composition is characterized in that the rare earth oxide in the composition consists of particles with an average diameter of less than two micrometers (2 .mu.m), and in that aqueous solvent includes a polysiloxane oil and a degreasing agent for diluting the polysiloxane oil.