Cook away—full speed ahead (but clean out the coffee residue first!) The 1917 Centennial Watch Mug™ is microwavable and ovenproof to 450 degrees Fahrenheit. One co-founder of Glass Beach Mugs, LLC, has a chef brother who is a graduate of the Culinary Institute of America in Hyde Park, New York. When we told Chef Pierce about how the Marines who drank from mugs like these went to France and saved Paris, he served us French onion soup in them.