The Houze FX is the durable non-ceramic enamel used on these items to create it's unique thermochromic effects to prolong these effects it is recommended that these items are handwashed and not exposed to temperatures in excess of 170 Degrees F. Microwave over usage is recommended only with a temperature probe and setting at or below 170 degrees F. Prolong exposure and strong light may cause (hard to make out on paper) and should be avoided. Store at room temperature in a closet or other dark area. Cleaning with abrasives should be avoided.