All RIVSALT graters are comparable to a quality chef’s knifes. To keep them sharp, shiny and rust free we strongly recommend that you wash the graters by hand regularly using a mild dishwashing liquid and water. Use a brush to remove loose salt, pepper or other spices. After washing, rinse with water and dry thoroughly with a towel. The graters should not be put in the dishwasher. Doing so could damage the sharp edges. Please be aware that during hot weather and high humidity it is necessary to care a little extra for RIVSALT graters and clean them more regularly.