Lubricating oil, paint, etc.: These products can be filled using various filling machines. For lubricating oil, due to its high viscosity, a special piston - type filling machine may be required to ensure the smooth progress of filling; for paint, depending on its composition and viscosity, an atmospheric - pressure filling machine or a pressure filling machine may be used, and during the filling process, attention should be paid to avoiding the generation of bubbles to affect the product quality.