We recommend Diamond Stones be cleaned when they become discolored or noticeably clogged with metal shavings. We recommend cleaning your diamond stones after approximately 25 sharpening sessions.  To clean Diamond Stones, use dish soap and warm water. Run warm water over the stones, and then use a firm brush (an old toothbrush works great) and some dish soap to scrub the stones clean, then rinse. Dry the stones well with a towel and air dry the stones by standing them on end. Ultrasonic cleaners can be used to clean your Diamond Stones. If your stones are badly clogged with metal shavings, you can soak them in white vinegar for up to 10 minutes, then follow the above procedure. The vinegar will loosen the metal shavings.  For in-between cleanings, a few sprays of Windex and a paper towel work great.