These are very fast cutting and hard, they are particularly useful for 1st stage heavy duty mopping operations on steel and non-ferrous metals. They will remove grinding marks left from previous operations, when processing steel, stainless steel or non-ferrous metals and are usually used in conjunction with a coarse cutting stainless steel polish. Sisal stitched mops can be chemically stiffened to increase life and give a more aggressive cut for an extra 15% cost.