A good, sharp knife is key to preparing any meal at home, but even the best knives can dull over time. If you don't have a knife sharpener, reach for this DIY version instead: a ceramic coffee mug or terra-cotta pot. Unfinished bottoms on both surfaces are the perfect roughness for sharpening. Run your knife blade against it at a 45-degree angle. Do this for several swipes, and you'll have razor-sharp knives.