Particles may be used to filter oleo material such as grease from a flow of fluid such as a gas. The particles can be arranged into a bed to filter the oleo material from the fluid. The filtrate substance collect on the inorganic particles. The particles are re-usable, in that they can be subjected to filtrate-separation techniques, e.g., solvent extraction, detergent washing, and centrifugal separation, to separate the oleo material from the particles.