Keep multiple abrasive grain sizes on hand to sharpen blades. Convert leather and wood surfaces into sharpening stations to give your tool a fine finish. These compounds contain diamond abrasive grains, which are hard, fast cutting, and long lasting. They're used on leather strops and other flat surfaces to sharpen straight blades. To sharpen curved blades, you can also use these compounds on curved surfaces. Start with the largest abrasive grain size, then move to smaller sizes to sharpen your blade to a progressively finer edge.