If you make this mistake when cleaning your knives, you risk diminishing the sharpness of the blades, hastening corrosion, ...
Over time, as iron, steel, and other ferrous metals are exposed to oxygen and moisture they can undergo oxidation, a chemical reaction that eats away at the metal and rust your tools. Left long enough ...
Even if you've owned countless knives before, nothing prepares you for the black "rust" that develops on some of your knives.