Is WD-40 good for knife blades?

WD-40 is useful on some knife blades, but it is not ideal as routine blade care. It removes moisture, light grime, sticker residue, and some surface rust well, so it can help clean utility knives, shop knives, and pocket knives. It is not food safe, so it should not remain on kitchen knives or other blades that contact food. It also is not the best long-term protectant because it is thin and temporary. For kitchen knives, soap, water, and full drying work better. For carbon steel or collector blades, mineral oil, camellia oil, or a dedicated rust preventative protects the steel more effectively than WD-40 after cleaning.