Have you ever had a knife that was just too dull to cut anything? Well, you don't need a sharpener; simply grab a common household coffee mug to do the trick. Slide the blade along the bottom of the mug at a thirty degree angle to sharpen your blade. Not too roughly, just scraping it. This should sharpen that once dull blade, and you will be able to cut your food much easier in the kitchen. Don't have a sharpener? Then the coffee mug is your answer!