Subheading 591140 is specifically limited to filtering or straining cloth used in oil presses or similar machinery for making oil or the like. Filtering fabrics used in other industrial processes—such as liquid filtration in chemical plants or air filtration—fall under the residual 591190. The intended end-use in oil extraction is the decisive factor for 591140.

The split is purely by weight: 591131 covers papermaking machine clothing and felts weighing less than 650 g/m², while 591132 covers those weighing 650 g/m² or more. The weight threshold reflects differences in the forming, pressing, and drying sections of papermaking machinery where these felts are used, and accurate weight documentation is essential for correct classification.