The Naniwa Rust Eraser is essential if you use carbon steel knives or tools. Steel is extremely prone to rusting, especially when you are using these tools outdoors. And no one wants rust on their blades. Fortunately, removing rust is easy with the Rust Eraser from Naniwa.Use this to clean your carbon steel tool (scissors, Hori Hori, Pruners) prior to sharpening. This works great at getting off the daily gunk acquired like sap, dirt, and oxidation. The Rust Eraser is a soft and flexible block, 50mm x 40mm x 20mm (2" x 1-1/2" x 3/4") in size. The eraser is similar in consistency to a pencil eraser, the alumina abrasive is distributed throughout the entire thickness of the block, so fresh grit is exposed as it wears. The fine grit abrades quickly through rust. It can be used dry or with a little water or oil. Keep this in your gardening bag while you're out working in the garden so you can clean as you go!